Editing 1964-1990 Oldsmobile V8 engine information

'''[ Thanks to Joe Padavano, Bob Barry, Jeff Easton for this information ]''' 

I found this info to be very good so I thought I'd copy and paste for the good of the Crankshaft coalition. -ChevelleSS_LS6

In the year 1964, Oldsmobile came out with a new small block (330 CID), and the next year a big block (400 and 425 CID). Over the years other displacements were added. The Olds 455 was a 1968 introduction, developed from the Olds 425 introduced in 1965, which was a tall-deck version of the 330 engine design introduced the previous year, both of which replaced the 394ci V-8, which was a development of the design introduced as the 1949 303ci "Rocket" V-8. Production of big blocks ceased in 1976, although some were used, not necessarily in cars, in the 1977 model year. Production of small blocks ceased in 1990.

The big and small block engine types are almost identical, with the big block having a higher deck than the small block. The bore centers are the same, since the only differences between the small-block and big-block Olds blocks are the deck height (9.33" and 10.625", respectively) and the main journal size (2.5" and 3.0"; diesel 350 used BB size mains, however).

Many internal parts interchange, but it is best to keep the big block parts on the big block and the same for the small block.

The engines were sometimes named, and this was printed on the air cleaner label or sticker. Mid 60's 425s were known as Super Rockets. Some featured Ultra High Compression on their labels.
Quick Identification

The large oil fill tube on the front of the engine, sticking up from the timing chain area, is a dead giveaway that it is an Olds engine. The distributor is found at the back of the block and it does not go through the intake manifold, but right into the block. Also the spark plugs will be above the exhaust manifolds with no need for heat shields.

The Block Code and/or Head Code can give you an idea, but some codes cover many years. The casting number is ususally nearby. Other than that, there is no method of determining the year of manufacture of an Olds block.

The valve covers are a distinctive shape. Straight running front to rear, with an arc connecting each end of the two lines, to define front and rear. From their sealing surface, the covers are curved as they meet their top. The top of the covers are flat, like someone cut off the curved top.

The thermostat cover/radiator hose has a special molded in bypass pipe for the waterpump.

The day of the year of manufacture is the big number right by the distributor hole.

Original paint color can help identify an engine, or further identify it. However, since paint is easily changed, it should be used as supporting evidence, not as absolute indication of engine lineage.

The VIN derivative stamping or engine unit number is on the left most side of the block or head, on the driver's side, just below the cylinder head, toward the front. The pad is part of the engine and will indicate the year of manufacture, but that is usually rusted beyond recognition, and it can be changed by restamping. Basically it IDs the car in which the motor was originally installed. It can provide some circumstantial info but not a positive ID.

The VIN derivative on 68-up blocks doesn't tie directly to the type of car it was installed in (unless you have some way to unambiguously trace the last six digits of the VIN), however it can provide some indirect evidence. For example, if the production plant (third place in the VIN derivative) was one at which no 442s were built (KC, for example), then it obviously isn't a 442 motor. Of couse, you have no way of knowing for sure that the heads were originally installed on that block or not.

For example, what this proves is that it could be a W-30 short block, but it could also be a Toro motor. W-30s were only built in Lansing, so if the VIN derivative had shown some other production plant, you would have positive proof that it was not a W-motor. Of course, if the motor is still in the car and the car is positively a W-30 and the last six digits of the VIN match, then it is a W-motor.

If the engine was replaced under warranty, the pad may be blank. Rubbing alcohol and Q-tips help to remove the grime and grit from the stamping.

1964-67 V-8 Engine:
Code is stamped on the right cylinder head. Unfortunately, this only applies to what was originally the driver's side head. This code consists of a prefix letter (330 V-8=T (1964-65) or W (1966-67), 400 V-8 = V), then a production sequence number, followed by a suffix code letter (L = Low compression, E = 2-bbl export, G = High compression, H = 4-bbl export). A 2-letter code on the oil filler tube identified the engine.

1968-later V-8 Engine
Have the last six digits of the VIN number, the year of the block, and the assembly plant stamped on the driver's side of the block below the cylinder head. A 2-letter code on the oil filler tube identified the engine.

You can use the VIN derivative number to ID the year. For 1968 and up blocks, this number is located on a pad just below the cylinder head on the front left side of the engine. This number will be stamped on a machined pad on the front driver's side of the block, just below the deck surface. Typically it will be covered with a power steering bracket or something, below the number one spark plug location.

This number should take the form of "35Mxxxxxx" where:
3 = Oldsmobile division.
5 = year of manufacture (8=68, 9=69, 0=70, ..., 4=74, 5=75, 6=76, etc.).
M = location of manufacture (M = Lansing, B=Baltimore, X = Kansas City, Z = Fremont, CA, etc).
xxxxxx = last six digits of VIN of car that motor originally came in (original car's sequential production number).

The letter indicating factory must match the letter in the sixth position of the car's VIN (it should also, of course, match the factory indication on the body data plate - in other words, for a Lansing-built car, the sixth place in the VIN would be an "M", the body data plate should indicate "LAN", and the third place in the engine ID should also be an "M").

Now, obviously this doesn't provide all of the information you're looking for, but you do get something. Year of manufacture is nice to know. Additionally, the manufacturing plant may provide some info as to the motor's original use. For example, if the letter is an "X", that signifies Kansas City, which only produced full size cars (88s and 98s). Framingham (the letter escapes me at the moment) built only A-bodies. Lansing, on the other hand, built all Olds car lines (surprise), so an "M" doesn't tell you much.

If the motor has a number stamped which doesn't match the above, it's a non-original motor from another car. If it doesn't have any number stamped at all, it could be one of two things. First, it could be a dealer-installed factory service block, which would come without a VIN derivative. The dealer should have stamped the new block with the VIN derivative, but may not have. The other possibility is that it's a 65-67 block (ie, a short-stroke 400 or a 425), as these motors did not have the VIN derivative stamped on the block. Note that obviously this latter option can be checked by looking at the block casting letter ("D" for the 425, "B" or "E" for the 400 - as opposed to "G" for the correct 68 long-stroke 400).

Some blocks, before 1977, have thier ID cast above the right hand center freeze plug, eg. D for 425, F for 455. Olds didn't cast the displacement into the side of the blocks until they went to the light weight design in 1977. The 1977 and newer blocks will have the cubic inches cast in large raised numbers right above the right hand center freeze plug, eg. 403. The 307 will be in liters (5L), and a diesel engine will have the letters "DX" on it. The engine VIN letter will also be cast into the side of the block. Note that the 260 blocks sometimed have the last 3 digits of the casting number cast there, "355", which is rather misleading.

The VIN in 1972 and newer cars tells you what engine the car came with.

The number stamped on the oil filler tube is the engine unit code. The first number indicates the year the engine was assembled and the remaining numbers refer to the sequence number of the engine assembly (for identification at the engine assembly plant). This number has no link to any of the VIN data of the vehicle and does not contain any codes that identify the engine size.

From the factory, the oil filler tube had a sticker containing two letters which indicated components (carb, etc), model application (Cutlass, 88, etc), and other configuration items (timing, CA approved, etc). See the chassis manual for a list of available configurations. In 1973 and later, the factory did tune the emissions packages to the specific models that an engine might be installed in, but before that, in general terms, most engines were the virtually the same across all model lines.