• PARTS INTERCHANGEABILITY
  • I'm swapping engines. What brackets/mounts will work?
  • Are there any differences between Oldsmobile V8 water pumps?
  • Which cast iron Olds exhaust manifolds can I use when doing an engine swap?
  • Are small block and big block Olds headers interchangeable?
  • Will a big block Olds oil pan fit my small block?
  • Will a cam designed for a 330 will work in a 455?

• GENERAL ENGINE
  • What is the difference between an Olds 'big block' and 'small block'?
  • How do I determine the year of manufacture of my 455 block?
  • Is there a way to determine if the engine matches the chassis?
  • Identifying a 39-degree angle block
  • Identifying Olds cylinder heads

• REPAIR/MODIFICATIONS
  • The aftermarket thermostat housing on my engine leaks. What can I do?
  • I want to block off my intake's heat crossover. What are my options?
  • I want to install an adjustable valvetrain. What do I need?
  • Is it really important to install hardened valve seats in a street motor?
  • My hi-po 455 is pinging pretty bad. Where do I do?
  • How do I install a replacement oil dipstick tube?
  • Rear main seal
  • I'm seeing a lot of condensation from my 442's exhaust pipe. What's the story?
  • What does the PCV valve do on my Olds, and is it needed?
  • I believe my engine has a dead cylinder. How do I find it?

• HIGH-PERFORMANCE PARTS
  • I want to install exhaust headers. What should I get and what problems might I see?
  • I'm replacing my stock cam with a performance unit. How do I check preload, to ensure longer pushrods aren't needed?
  • I've heard about cylinder head porting for better performance on my Olds. Please explain.
  • How do I hook up my aftermarket tachometer?
  • My radical cam is killing the vacuum to my brakes. What can I do?
  • I purchased a rebuilt carb for my '69 442 and was wondering if there is a rule of thumb for initially setting up carb.

• MISC.
  • Did all '67s come with a fan shroud?
  • What are the flow numbers for Oldsmobile cylinder heads?

What is the difference between an Olds 'big block' and 'small block'?

The problem is that the terms "big block" and "small block" have no formal definition. The terms most likely came into being when Chevy introduced the Mark IV engine family (396-427-454-etc) after producing the small block motor for years. The two completely different engine families led to the big block-small block nomenclature, which has been extended to most other auto manufacturers. In some cases the use of these terms is completely erroneous, as with the use of "big block" in conjunction with Pontiac, for example (all Pontiac blocks are externally the same size). Others, such as Ford, have multiple, non-interchangeable big block and small block families (why am I not surprised that Ford serves as the perfect example here). I've even heard the terms used to refer to engines other than V8s (such as the "big block" BMW straight six).

In the case of Oldsmobiles, conventional terminology refers to the low deck motors (260-307-330-350-403) as small blocks and the tall deck motors (400-425-455) as big blocks, though in reality both are the same basic engine architecture with the primary difference being deck height (Chevy, for example, makes tall deck big block motors for truck engines, but these are still called big blocks). The first generation Olds V8s (303 through 394) really never got the big/small designation, probably because for virtually their entire production run there was only one block size.

How do I determine the year of manufacture of my 455 block?

The only way to determine the year is to check the VIN-derivative. This number is stamped on the pad on the driver's side front corner of the block directly below the number one spark plug. Note that the pad where the number is stamped is on the block, not the head, so look just below the deck surface. The number should take the form of:

31Mxxxxxx

where:

3 = Oldsmobile division
1 = year of manufacture (1=71, 4=74, 8=68, etc)
M = manufacturing plant (M=Lansing, X=Kansas City, etc)
xxxxxx = last six digits from VIN of car in which motor was originally installed

If there is no VIN-derivative stamped on the pad, the block is probably a service replacement unit. If the number does not take this form and has an "L" in it, it's a marine motor.

Is there a way to determine if the engine matches the chassis?

There are no VIN on these years...just unit no. and date codes and as such you can only make sure the motor and external parts are correct and manufactured in the same time-frame. Since the '67 was still a package car it makes it easier for people to change the motor and other components.

I'm swapping engines in my 442. What brackets/mounts will work?

MOTOR MOUNTS First, the distance from the motor mount bolt holes on the block to the crank centerline is the same on both big and small blocks. Second, for 1968 and earlier cars, the frame mounts AND motor mounts are the same for both big and small blocks. On the 1969-1972 cars, different frame AND motor mounts were used on big and small blocks. This is NOT due to the differences in the block but instead due to a redesign to the rubber motor mount to provide an internal "fail safe" feature that retained the motor even if the rubber broke. This redesign caused the rubber mount to be taller, which required the frame mount to be redesigned. Here's the important part to remember: So long as you use motor and frame mounts as matched sets - that is, big block motor and frame mounts or small block motor and frame mounts - either a big or small block will bolt in with no problems. The crank centerline will be in the same place relative to the frame. You will definitely have a problem if you try to mix big block motor mounts with small block frame mounts (or vice versa). They will not line up properly and will need to be forced into place. If you sit the BB and SB motor mounts side by side, you'll see the difference in them. With the SB mounts on the BB, it'll raise the engine up in the chassis about 3/4" or so. Either use small block motor mounts with small block frame mounts or big block motor mounts with big block frame mounts. Note that the redesigned big block motor mounts ARE a better design, but I've installed many big block Olds motors using the small block mounts and had no problems with the rubber cracking, even when racing. If you go this route, just be sure to inspect your motor mounts periodically (as you should anyway).

The external dimensions and bolt holes on all 330/307/350/403/400/425/455 Olds engines are the same. If you're using a Toronado 455, you'll have to find brackets from a RWD car. All of the RWD V8 brackets are designed to fit both big and small blocks; some have two sets of holes, others mount such that the extra deck height doesn't matter. (However, the Toronado brackets are different due to the low hoodline of that car.) The prime dimensional difference is the height/width of the big blocks versus the small blocks. However, modifications will probably be required to the alternator bracket...and problems could be encountered if you attempt to put an R-4 A/C pump on the 455. There is no such bracket for this unit. You can take two brackets off a 350 and cut them in two and splice them together to achieve the correct height. I doubt that you will be encountering this, I just threw it in for kicks.

Big block frame mounts must be used with big block motor mounts, small block mounts with a small block. Either will interchange, but mixing the two will result in your engine sitting higher in the engine bay. The main motor mount bolt holes between the two won't line up either.  I have the SB motor mounts on my BB and have not had any clearance problems. (It can actually help with the clearance on of deeper aftermarket oil pans.) Basically, since the external dimensions/bolt-holes of the two styles are identical, when you swap from a small block to a big block, just use the same frame and motor mounts from your original setup. If you purchase new mounts, be aware that some parts outlets have the same part number for the BB and SB mounts, so beware...you might get lucky, but they ARE different. If you go in and ask for a motor mount for a '65-'68 big block car, you'll get the taller '69-'72 mount, which will not work. There are so few of these older cars on the road that the big parts manufacturers don't care to investigate these problems. The bottom line is to always bring the old part when possible and compare.

Swapping from a small-block to a big-block  -  If you're swapping in a Toronado 455, you need to use the accessory brackets, pulleys, and water pump from your small-block. You'll need belts for a 455 in a Cutlass. You'll need to use the oil filter adapter from the 350. You'll also need to either get a high-torque starter or swap the nose from your 350 starter onto the Toro starter (your small-block starter will probably work, but unless you've changed it, it's a low-torque unit that will be marginal on the 455). Yes, the Toro oil pan will fit your chassis. Finally, yes, the intake and headers will bolt on.

NOTE: The 307 uses different brackets that fit a small block only. You'll need to get an early set of brackets...any '68-'76 brackets should work. They don't need to be from a 455. If you're determined to make the 307 brackets work, here's what you need to know:

The power steering bolts to the block so you're OK with that...even uses the belt for the 307. The alternator bolts to the head, so no problem there except for that a longer belt is needed. The alternator bracket bolts to the power steering bracket and all you need is a longer bolt and nut and a spacer. You can use a 3/4-inch long piece of 1/4-inch pipe, which will work fine and is hard to see. The A/C presents some real problems but they are not insurmountable. The A/C brackets bolt to both the water pump and the head. If you lengthen the water pump bracket the compressor ends up sitting way too high and will not clear the hood. Thus, you'll have to lower and move the compressor outward. This clears both the hood and the head. It'll take some trial and error to get the brackets in the right place and welded up. However, the belt will end up being very long and when you get on it hard the belt will probably get tossed.

Want a cheap engine torque strap? Drilled a 1/2" hole all the way through the drivers-side motor mount and put a grade 8 bolt/nut though it and tighten it down. You'll have to clearance the frame pad.

To all you guys swapping a V8 Olds into a 231-V6 car: According to GM, the metal frame mounts that are bolted to the cradle are different between the V6 and V8. The V6 mounts are taller. Just something to keep in mind.

BTW, GM lingo calls the rubber engine mounts "brackets" and the metal frame pads "mounts".

Are there any differences between Oldsmobile V8 water pumps?

There are actually three different Olds water pump lengths. The measurement you care about is from the gasket surface of the pump (with the gasket removed) to the front face of the flange that the spacer or fan clutch bolts to. The three pump sizes are:

• 5.947" - all Olds motors with A/C
• 5.572" - B and C body without A/C
• 5.072" - A and E body without A/C

Note that the "with" or "without A/C" really applies to the pulley set that you are using. The pulleys and accessory brackets are designed to match the pump, so if your car had A/C and you removed it but are still using the A/C accessory brackets and pulleys, get the A/C pump.

One other item to note is that some HD cooling cars used the longer A/C style pump even though they did not have A/C.

Will a cam designed for a 330 will work in a 455?

No, but only because the 330 has the 45-degree lifter bank angle, vs the 455's 39-degreee bank angle. Everything else (cam bearing diameters, cam length, timing gear) is the same between big and small block Olds motors, but using a 45-deg cam in a 39-deg motor will result in at least one bank of cylinders having their valve timing grossly out of whack.

I want to install an adjustable valvetrain. What do I need?

Small block Ford 3/8" stud mount rockers interchange with Olds. AMC 3/8" rockers also interchange. You will need the Competition Cams 5/16" lower stud/3/8" upper stud and guide plates for mounting the roller rockers. You MAY also need custom/adjustable pushrods.

Is it really important to install hardened valve seats in a street motor?

Lead in gas has two functions: raise the octane level and lubricate the exhaust valve seats. If lead is missing in the fuel, the exhaust valves hammer away at the seats. The lack of lubrication wears the seats. This is called valve recession. The worst condition is a constant high RPM operation. If this motor has been run for years on unleaded gas, then there is a good chance that the recession is already in progress. I would recommend that you install them.

First, they will need to be hot-tanked, Magnafluxed, and checked for straightness. I always go for new iron valve guides and hardened exhaust seats. Make sure the machine shop knows and uses the appropriate seat for Olds heads. They should be about .22" thick. Thicker ones will result in cutting into the coolant passages.

Be absolutely sure you know the difference between bronze 'guides' and what most shops use bronze 'liners'. The liners are bronze but are just that...'liners'. I myself prefer an actual replacement guide. These guides are sometimes called 'thin wall'. In order to use the 'thin wall' type the old guide must be bored out, this process is done on a seat and guide machine. A "thin wall" cast iron guide is usually good for the life of the rebuild. A bronze 'thin wall' is more suited for racing and high load applications. You're probably looking at double the cost for the bronze 'thin wall' guides over the cast iron.

Anything else will depend on conditions and what you want done. If the heads are warped or corroded, something will need milled. If you are using a stock rocker arm setup, you will need to have the valve stem height set (tips of the stem are all at the same correct height). Your valve springs are probably worn out, so you should replace them with springs to match your camshaft.

Stainless steel valves are always better than the stock steel valves. The stock valve guide "seals" are pretty cheap, so I like to use Perfect Circle VS-100 which is a rubber seal with a Teflon insert in the hole.

There are a couple of ways around using hardened seats in a street motor. One is to simply run leaded fuel -- I get mine from a little airport in five gallon jugs. Low lead 100 aviation fuel has WAY too much lead for cars, so don't run it straight up -- I mix about five gallons in a twenty gallon tank. If your seats were cut during the valve job, its too late for this trick, but hardening of valve seats occurs naturally when a motor is run-this is called "work hardening". If you can get by with just a lap, no major grinding, and run stainless valves (they don't retain crud the way a steel valve does), you can get by without hardened seats on a STREET motor-heavy runs at the strip not allowed. This has worked many a time for me also. The main thing to remember is not to hammer on the motor too hard unless you got some leaded fuel in the tank.

I want to install exhaust headers. What should I get and what problems might I see?

For a lower tuned daily driven car use headers with smaller diameter, longer length primary pipes. 1.75" primary pipes are probably best and if you can get them 40" long pipes. The smaller tubes keep the hot gasses from expanding which keeps the velocity up, the length keeps it from hitting the collector and expanding until the next exhaust pulse is ready (low RPM). When the pulse finally hits the collector and exhaust pipe the created low pressure in the next tube will pull exhaust from the next cylinder reducing backpressure. There are 1.875" and 2" primary headers but these will reduce the scavenging effect at lower RPM (unless you are pushing a brutal amount of air at low RPM...say with a blower or something). High RPM engines are generally more concerned with flow since an engine spinning at high speeds will impart substantial velocity to the exhaust gasses anyway.

There have been reported problems with driver's-side header installations on '66-'67s, with reports ranging from interference from the steering shaft, frame, and even the starter.

To facilitate the installation of headers on virtually every situation -

• Move the brake distribution block to the top of the frame rail
• Grind about 3/8" from the rear of the lower driver side control arm mount
• Grind down a portion of the passenger side upper a-arm.
• You'll have to remove the starter and oil dipstick tube, and you might also have to put a small dent in one header tube.
• The passenger side might require temporary removal of the oil filter housing for fitting.

Hedman headers are a good fit, not hanging too low. Swap-meet Blackjack headers are reported to fit well. Since then, Dynomax purchased Blackjack, so their headers are a match...plus, you can get them aluminum-coated.

Which cast iron Olds exhaust manifolds can I use when doing an engine swap?

Big block stock cast iron exhaust manifolds are longer due to the increased block height. In other words, they reach down farther. When swapping exhaust manifolds, you could possibly run into problems with interference with the starter or oil filter, and/or the outlets may be in an awkward location. Be sure to compare before installing.

All small block exhaust manifolds are of a small, open plenum design. They are poor performers for a 350 and will be really restrictive for a 455. Some use the 307 exhaust manifolds because the outlets were a bit bigger than the 455 manifolds. You can take your old trusty die grinder and slightly port the manifolds and remove casting flash etc. inside of them.

Second, if you're keeping the small block manifolds because you want to use the 350 exhaust pipes when swapping in a 455, forget about it. The 455's taller deck height will prevent the pipes from fitting (they'll hit the floorpan at the base of the firewall). You stand a better chance of getting the pipes to fit if you use the correct A-body big block manifolds.

Will a big block Olds oil pan fit my small block?

Yes, they will work just fine...the only difference is that the big block pans have an additional bulge just forward of the sump, presumably to clear the longer crank throw while still providing enough clearance for oil drainback. The 455-equipped Toronado pan will physically fit and will increase oil capacity by one quart, but it's a poorly designed pan for a rear-wheel-drive car. The Toro pan has a front hump that looks like it traps about a quart of dirty oil. So, yes it has a 5 quart capacity (6 w/filter) but you will never get the last quart out. AND, there is no baffle on the bottom, so you will have to add one. I would go aftermarket if I wanted a larger capacity pan. If you DO decide to go with the Toro pan, remember to get the pickup off the pump. There is a difference between that and a standard pump pickup.

Another feature of the big block oil pan is the tack-welded oil baffle. It sits on the edge of the sump portion of the pan. Under braking or hard acceleration it helps to keep the oil in the large pick-up area of the pan. Most small block pans do not have a baffle to help keep the oil in the sump area. This feature alone is worth using a big block pan on a small block application.

FYI: The 455 pan will fit the 350 but the 350 pan will not fit the 455 motor. The crank will hit the bottom of the 350 pan.

I've heard about cylinder head porting for better performance on my Olds. Please explain.

For a street vehicle the last thing you want to do is enlarge the port area. This will reduce air velocity at low engine speeds, and decrease the cylinder's volumetric efficiency (VE) which means the cylinder won't fill all the way until the RPM is pretty high. The basic idea is to make the air flow smoother with less turbulence, there are various ways to do this. Remove all the sharp edges. There are specific key areas to do this. The 2nd most important area on the intake side is to reshape the valve guide boss into a more aerodynamic shape, usually referred to as "tear dropping", because that's what it resembles once finished, and to smooth the area where the bowl meets the valve seat "blending". On standard heads the bowl area does not make a smooth transition to the valve seat which causes lots of turbulence, inhibiting air flow. There are typically sharp edges on the short turn side of the runner, sort of like steps. These can be smoothed but this is not usually done for standard street use. Usually its a good thing to polish the combustion chamber to help prevent pre-detonation when running high compression. With a totally smooth surface, you don't develop as many hot spots. On the exhaust side its almost mandatory to remove those AIR bumps from the top of the exhaust port, its also a good idea to polish the runner as much as possible to reduce air friction. Basically the easier the air can travel through the runner the less power your engine has to use to force the air out of the cylinder leaving more power to turn your crankshaft. You probably shouldn't polish the intake runner though. If you are porting the heads for street use you'll want to do the bowl to valve seat transition, valve guide boss, exhaust port. You could call this a "street/strip" port I guess. A pocket port usually would just entail the doing the bowl area. A full port job usually means doing all what I have mentioned plus enlarging the ports to flow more at higher RPM. Strictly for race engines I assure you. Now to the cost, its fairly expensive to get a street port. I have seen street ported heads going for as much as $1000 (depends on the shop). The best thing you can do is give them a list of what you want and get them to quote you a price.

I'm replacing my stock cam with a performance unit. How do I check preload, to ensure longer pushrods aren't needed?

Hydraulic lifters are usually supposed to have .050"-.080" pre-load. One simple way to check preload is to tighten the rocker arms down and measure the clearance between the lifter plunger and its retainer ring. You will need some sort of gauging wire to check that. Another way to check it is to tighten the rocker arms until there is zero lash and then see how much further the bolt turns before the pedestal contacts the head. Find zero lash by spinning the pushrod while tightening the bolt. As soon as there is resistance to spinning the pushrod, you have found zero lash. With a rocker arm ratio of 1.6, the bolt will need to be screwed in about .050" further to get .080" lash. With 5/16"-20 bolts, that will require that the bolt be turned one more complete turn before the pedestal bottoms. You could also use a feeler gauge to check for .050" clearance between the pedestal and head when you have zero lash.

What does the PCV valve do on my Olds, and is it needed?

All internal combustion engines produce blow-by gases- fuel and oil vapors that get past the rings and must be removed from the engine to keep oil reasonably clean and free of condensation and other impurities. The Positive Crankcase Ventilation valve accomplishes this by sucking the blowby gases back into the intake manifold under vacuum and reburning them in the engine. There can be either open or closed PCV systems. Open systems use a vented oil fill cap or breather filter to allow fresh air into the engine so it doesn't vacuum lock. Closed systems (used on all Oldsmobiles since 1968 and California ones since 1962) get their fresh air from inside the air cleaner housing thru a tube and breather filter on the valve cover. This is so blowby gases and oil vapor can be sucked into the engine thru the air filter element and burned instead of going into atmosphere.

Earlier cars (pre 1962) had road draft tubes extending from the top of the engine to the bottom of the car. Airflow over the open end of the road draft tube induced a vacuum in the engine and pulled impurities out of the engine right into the atmosphere.

So yes, you need a PCV valve or some other way to evacuate blowby gases. It keeps oil cleaner, reduces sludge, and as long as the crankcase is under vacuum from the PCV system, the outside of the engine stays cleaner. If you ever see an engine that the PCV wasn't working, it'll be coated in oil that blew past all the seals.

The PCV valve regulates the amount of air being drawn from the crankcase. At high manifold vacuum, the valve seats to limit the flow. At low vacuum (WOT), the valve unseats reducing the restriction to allow a comparable amount of air to flow with the lower vacuum source. High vacuum, high restriction. Low vacuum, low restriction.

I believe the closed system was also introduced to reduce emissions on aging vehicles. The PCV cannot keep up with a tired engine with lots of blow-by, especially at WOT. Oil in the air cleaner housing is a tell-tail sign of a dead engine. The open system will let excess blow-by to the atmosphere.

If you look at a vacuum gauge, they usually have a mark at the low end for PCV checking. The crankcase should normally be a few inches negative. Connecting a vacuum gauge to the crankcase is a good determiner of engine health (stock engines).

W-30s DO have a PCV valve. It is plumbed into a hole in the intake manifold that goes into the lifter valley.

Most '67s I've run across had a PCV valve in one valve cover and a breather in the other. As far as which one goes where, it depends on whether the car has the Climatic Combustion Control system (huge, weirdly shaped air cleaner with twin intakes), cruise control or California emissions package. Also, factor in that there may have been a difference in closed and open PCV systems, which having a breather, yours is open. Closed systems took their fresh air from the aircleaner via a tube. Functionally, it won't make any difference which side the components are on.

The aftermarket thermostat housing on my engine leaks. What can I do?

Chrome aftermarket water necks are frequently warped. Get a piece of fine wet/dry sandpaper, put it on a piece of glass (for flatness) and run the base of the water neck back and forth over it. If the sandpaper does not evenly sand the bottom of the water neck, then you can see where the warpage is. If the neck is aluminum or pot metal, continue sanding until flat. If it's cast iron this might take a while and you may want to get another.  Then be sure to use Permatex sealant on both sides of the gasket when installing the water neck.

If the sandpaper trick shows that the neck is flat, you've got a problem with the manifold.

I'm seeing a lot of condensation from my 442's exhaust pipe. What's the story?

A lot of people have the bad habit of starting up their "garage queens" every week or so and letting them run for only 15 minutes or 20 minutes instead driving them for at least 30 minutes (or longer). This allows condensation to continue to build up in both the exhaust system and engine oil...in other words, they're doing their cars more harm than good. If you drive your car regularly, allowing a full warm-up, and the outside temps are warm and still had condensation after an hour I might be a little concerned, but it's only water. If it were antifreeze, it would be white smoke coming out your exhaust, not liquid (you're not running straight water in the radiator are you?). Cars that sit really need to be started and run long enough for the condensation to evaporate from the crankcase and the exhaust system. Don't be a sissy...let those four barrels breathe once in a while! In other words, I wouldn't be too concerned with the condensation, but I'd still keep an eye on it, just in case.

Incidentally, this phenomenon is the single fastest factor is an exhaust system rusting. For cars that are stored for any period of time, it's always a good idea to stuff some rags into the exhaust pipe to seal them, or to slip a plastic sandwich bag over the tailpipe and secure with a rubber band.

How do I install a replacement oil dipstick tube?

Try putting it in the freezer for a few hours. As the metal gets down toward zero degrees it'll shrink and you should be able to tap it in without damaging it. Once it warms up it'll expand and seal itself properly. If you still have trouble inserting the tube after freezing it, you might have to sand the round part of the tube that goes into the block down just a bit. Then stick a bolt inside the tube and use a small ballpeen hammer to tap it in.

How do I hook up my aftermarket tachometer?

If it's a Sun Super Tach II and unless they changed it-White is the internal light. Red goes to 12v source. Black goes to chassis ground. Green is the trigger wire which has to be connected to the coil (-).

In order:

• Connect the GREEN wire to the coil (-) post.
• Connect the RED wire to a switched 12v circuit at the fuse block (spare blade terminals labeled IGN or ACC).
• Connect the WHITE wire to either the dash light circuit (tap in on load side of the INST LPS fuse) or an ACC terminal.
• Connect the BLACK wire to a good chassis ground under the dash.

Try to stay away from splicing into wires behind the dash. It makes a fire hazard. Use insulated terminals and special fuse taps. It looks and works better.

My 455 detonates (knocks) any time I punch it. The motor was bored .030, TRW 10.50 pistons, JM20-22 cam, "C" heads with hardened seats, perf. intake with 800cfm carb, MSD distributor and box, and AC RS45 plugs set at .045. It does have a more or less stock exhaust system. I run 92-octane gas with a bottle of 104 octane boost per tank.

• With 10.5:1 compression, 92-octane will ping pretty good. You will need to go to a local race track or airport and get some GOOD gas, like 114-octane leaded. Put 5 gallons in every tank with some 92-octane premium.

  • Do not buy aviation gas because it is formulated to run in low RPM (3000-3500) engines and thus has different burn rates. Also be aware of the so-called octane boosters in a bottle. Sunoco did a test on 8 different brands. Three of them actually lowered the octane rating! None worked as advertised. In order to get the advertised increase rate of octane they had to use 3-4 times the recommended rate. That put the cost per gallon over $3! Might as well go to the drags and buy the real stuff. Sunoc(?) has a great GT 100 just for 60-70's cars.

• Make certain the engine is running cool...with that much compression, a 160-degree thermostat and a cooling system which can keep it in that range is recommended. Also it's better that the carb be getting some kind of cool outside air and not sucking the hot underhood air.

• The spark plugs mentioned are probably too hot for that much compression. R45S plugs are more suitable for 8.5 or 9:1 compression. Try some R44S or R43S plugs to cool it down a bit.

• Try running the car with the vacuum advance disconnected first. To check timing properly get a dial advance timing light! If you don't know how to use one, ask somebody who does. You are risking serious engine damage. The MSD is a tunable distributor...read the instructions and limit your distributor advance to 20 degrees to start with. Select the spring combination to give full timing advance by 3000 rpm. Put the distributor in the car and start with around 12-14 initial timing (that's what you read with the engine idling). Check the timing at various engine speeds, then make sure it does not exceed 34-36 degrees after 3000 rpm. By adding the distributor advance's 20, plus the initial advance 12-14, you get 34-36 total degrees advance.

• Adjust your mechanical advance rate in the distributor, controlled by the tension springs. You may need to just SLOW down the advance rate of the mechanical advance by using stiffer springs. The mechanical advance weights are linked together so they always swing out an equal distance. Thus, the two springs work together, the sum of their force pulling both weights in. In fact, using two springs of different rates is a common way to modify your advance characteristics. Can't decide between stiff springs and light springs? Use one of each to split the difference.

• As a last resort, have your carb's air-fuel mixture checked under load (the point at which it pings). There is a fuel enrichment circuit for acceleration and it may not be working. Look for about 12:1 air-fuel ratio under acceleration and around 14:1 at cruise.

• One last point to keep in mind; my understanding is that TRW rates its pistons based on a 70cc combustion chamber. The C-type heads you have should be more like 79 or 80 cc's, so your compression is way less than 10.5, probably closer to 9.5.

rear main seal

A rope seal can work on a race motor if the installer is experienced at seating it properly but the neoprene seal will always have less drag. In place of the factory rope seal, use the neoprene rear main seal made by Fel-Pro. (PN BS-6141). This part number isn't a listed number for the Olds small blocks, but is listed in the April 2000 issue of Car Craft (page122). This part # is an AERA recommendation.

First, polish the knurling off the neoprene seal to ensure longevity. Install the two pieces with a 1/4" offset...that is, one side lower than the other in the seal groove. This will greatly diminish the possibility of leakage. Make sure the lip is facing the front of the engine and coat it with lube so you don't have a dry start-up. And don't forget to put a small amount of sealer on the mating surfaces of the rear main cap.

If you can't find the neoprene seal, you have two options:
1) Get the Victor seal for a Ford 429/460. This package lists the following applications: Ford 429, all '68-'78 460, '79-'81 370, '79-'95 429 and '73-'95 460 trucks.
2) Fel-Pro BS 40032, which is a rubber piece.

Go to a local NAPA store and order part #JV618. It is the correct seal for an Olds 455.

Did all '67s come with a fan shroud?

The radiator fan shroud that was used on '67 A-body models was the same design as '66. A fan shroud was used when you ordered either C60 car air conditioning or Y76 Heavy-duty cooling (Y76 was included with CAC). A Cutlass with the L78 442 package would have come standard with a 2-core radiator and a 4-blade fan, in either an automatic or sycromesh. One would get the 55-amp alternator, CAC water pump, 6-blade clutch fan, three-core radiator, radiator shroud and hood seal with C60 and Y76. You could not factory order C60 or Y76 when the car was equipped with a rear axle ratio of 3.90 or lower. The higher engine burst speeds with the lower axles were of a concern to Olds. This might cause a problem if the fan or compressor clutch engages at speed. Hence, that was why you could not get C60 and Y76 on early W30 cars.

The shroud was attached to the upper radiator support on top but used two Z brackets to attach to the lower support.The shroud had been reproduced and sold by Year One. Y76 cars are quite rare, but the pieces to add the option are pretty easy to find.

I want to block off my intake's heat crossover. What are my options?

Some people argue it is a warm-climate-only modification. If the car is a northern park-outside driver, I might think twice. Otherwise go for it. There are a few options. You can use the Edelbrock cast iron plugs in the heads. They work absolutely fine. They do require some custom grinding to fit into the heads. However, there HAVE been reports of these coming loose and rattling around.

One of the things about the plugs is they only block the heat from the intake. They do nothing for the interconnection of the two exhaust ports and the “which way should I go?” center four exhaust ports. The general consensus is molten zinc is the ticket. Its expansion is supposed to be similar to the iron. I personally use furnace cement (Irontite brand). You can blend it nicely in the bowel area easily. I have only had it come loose once and attribute it to me rushing the job with heat lamps, possibly creating air pockets. Remember if you block the risers you will have to come up with an alternative to the factory choke, as there will be no heat to operate it.

You could also purchase some alloy from Mondello for plugging them. It will have to be melted and poured in. I've also heard of people using old pistons and melting them and pouring them in.

What are the overbore limits for a 455?

According to the experts (Mondello and Miller) a 455 block can be bored +.125. However, I have heard of some people having difficulty at +.060. If you want to be sure, have it sonic tested. That will be able to tell you if your block can handle it. Blockwise, the older blocks ('68-'72) have a higher nickel content and so are a better choice for large overbores (as compared to the '73-'76 blocks.)

Are small block and big block Olds headers interchangeable?

No. Due to the taller deck height, big block Olds headers have a greater vertical dimension than small block headers. Additionally, small block headers typically use smaller diameter primary tubes.

My radical cam is killing the vacuum to my brakes. What can I do?

Use a vacuum reservoir. This extra reservoir is usually the size of a small coffee can 5X7. It goes between the vacuum manifold line and the power booster. The vacuum reservoir also comes with a check valve. Summit Racing makes several different ones. Purchase the most basic one and hide the tank up in the driver's fender and hide all the vacuum lines. You won't be able to tell something was added. It will bring back the power brakes nicely. Cost of the tank is between $35-$40. GM (and likely others) used them. Mid-'80s Cadillacs had them. Standard Motor Products sells replacements for the factory versions.

Q: I purchased a rebuilt carb for my '69 442 and was wondering if there is a rule of thumb for initially setting up the carb.

A1: Do you have any Olds repair manual for that year? It will tell you all the info you need, like how to set the float level, choke, and fast idle. Many of the adjustments on Quadrajets are done by slightly bending certain linkages. This, too, is covered in the Chassis Service Manual for your year. Follow their diagrams in sequence, as making one adjustment can affect others.

The one item that is not covered in the manual (if I remember correctly) is adjustment of the idle mixture screws -- one of the first adjustments you'll want to make. The manual doesn't cover this because the factory supposedly optimized that adjustment for emissions, and they didn't want you monkeying with it. But if you've changed cams or compression or you're starting out with a rebuilt carb, it needs adjustment.

As a starting point, turn both idle mixture screws all the way in, then back them both out 3 turns. With a warm engine (no choke), adjust the idle stop screw to the specified rpm. Now go back to the idle mixture screws and adjust them richer or leaner until you maximize the rpm. Always adjust them equally. Back off the idle stop screw to specification again, then adjust the idle mixture screws for maximum rpm again, etc. When you've reached the point where the idle is at specification and further adjustment of the idle mixture screws only drops rpm, then adjust them 1/4 turn at a time, leaner, until the rpm drops 50. Then bump the idle back up 50 rpm with the idle stop screw. You want your idle to be on the lean side of perfect.

I hope I didn't make that sound too complicated. It's not.

                           Cylinder Head Type
                
Valve Lift  A  B  C     D      E      F   G & Ga  H     J      Ka

      .100       80    87     84     87     86    82    76     80   
      .200      153   155    147    156    149   150   136    148
      .300      199   195    203    198    193   197   194    197
      .400      220   215    229    214    212   219   210    211
      .450      230   220    232    221    218   225   212    218
      .500      236   225    236    226    223   229   214    223
      .550      239   229    238    228    224   231   214    224
      .600      244   231    239    230    225   234   214    225
      

                            Cylinder Head Type
                  
Valve Lift  A  B   C     D     E      F   G&Ga     H    J     Ka  

    .100          46    47     45    46     44    47    46     44
    .200          93    92     87    93     91    92    84     89  
    .300         125   125    120   122    122   124   114    119
    .400         137   139    139   136    137   139   118    136
    .450         142   144    144   140    142   144   119    141
    .500         149   148    149   145    147   149   119    147
    .550         151   153    153   149    149   153   120    150
    .600         153   157    157   153    152   156   120    152

Q: I believe my engine has a dead cylinder. How do I find it?

Here's a simple test that can quickly and cheaply determine the relative performance of an engine, by cylinder comparisons.

What you'll need:

• 8 1" to 1.5" sections of 1/4" carbon impregnated vacuum hose (which loosely translates to "used" stuff...)

• A couple feet of electrical wire (alligator clips on each end helps, or at least a couple inches stripped off.)

• A screwdriver, with an insulated handle (or some other test probe, whatever happens to be handy)

• A tach, paper, and pencil, and stopwatch may be of benefit, too

What to do:

• Step 1: With the engine OFF, remove each plug wire, at the cap, one at a time.

• Step 2: Insert a section of vacuum hose between the cap's tower and each wire, making sure the wire and hose fit snugly together on cap

• Step 3: Repeat steps 2 and 3 until all cylinders are accounted for ;) You should end up with a set of plug wire extensions above the cap.

• Step 4: Connect one end of the electrical wire to a reasonable ground location (fender, frame, alternator bracket, etc.

• Step 5: Connect the other end to the screwdriver/probe.

You may now start the engine, and allow it to idle.

Touch the probe (screwdriver) to the vacuum line extensions, one at a time, for about five seconds at a time. Repeat for each cylinder.

This shorts out the plug wire, effectively killing the cylinder. Take note of the amount of RPM drop for each shorting. The higher RPM drops will indicate a stronger cylinder. If the RPM only drops a little, or not at all, or increases then you've found a dead/weak cylinder. The only thing that'll tell you is that that cylinder is not contributing to the power production of the engine... It's up to you to determine why. A bad plug, wire, or mechanicals are all causes, as are vacuum leaks on that intake runner, etc.

By watching the tach and stopwatch, and recording the RPM drops for each cylinder, you can get a fairly accurate representation of the engine's overall condition, much like a compression test. If electrical inspections don't reveal anything, then you may consider compression tests, leakdown testing, and/or other mechanical inspections.

Identifying a 39-degree angle block

There are a couple of ways to check for cam bank angle, and if it is a Toro 425 block (probably applies to all blocks): Find the engine ID number/letter on the shelf behind the water pump, ahead of the intake, just above the timing chain. Now, at the RH [passenger] end of this shelf is an upright wall that runs fore-aft. This means the block is a big block. It should get fatter toward the front. Right near the top, in the fatter part, there should be a drill spot, at about a 45 degree angle [parallel to the even-bank head bolt holes] and just barely drilled into the wall or rib, until the diameter got to about 3/8". If that drill spot is there, then the block is almost w/o a doubt a 39-degree cam block. Every 1966 to 1967 Toro 425 and 1966 to 1967 442 400 engine I have seen so far had this drill spot and had a 39 degree cam bank angle. Basically, the way it worked out was that if the early (pre 1968) big block had 0.921 lifters, it was an advanced [for the time] 39-degree block, and if it had the normal 0.842 lifters, it was an old 45 degree block. Anyhow, the presence of the drill spot on a pre-1968 big block means a 39 degree block and heads. Easy to spot, too.

the B cyl heads

1965 came in two valve sizes a 2.000 intake and 1.625 exh 80 cc  2 bbl heads and a 4bbl version  used on irrigation equipment both have number 389395 cast in cyl. head,  but the irrigation head uses a 2.070 intake and a 1.625 exh

1966 came in one version 2.070 intake and 1.625 exhaust, same cast number as 1965 used on 400/425  4-bbl; all are 80cc. Bank angles are as follows:

1965 block      389298 45 deg                          b block 400
1965 block      386525 45 deg                          a block 425
1966-67         390925 39 deg                          e block 400
1966-67         389244 45deg                           d block 425
1966            389244 w/drill spot 39 deg             d block 425
1967            390925 w/.375 drill spot 39 deg        e block 400
1967            389244 w/.203 drill spot 39 deg        d block 425
1967            389244 w/.375 drill spot 39 deg        d  block 425

So some B heads are comparable to C heads w/slight modification, but don't forget c heads also came in two valve sizes a 4bbl version and a 2 bbl version

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This page last modified on February 15, 2003.