Block Stamp Pad Question

[Steve G.]

When I purchased my '68 (327-300hp), I was informed that a new short block was installed by the dealer due to a spun bearing during the original owners tenure. This may have been the case since the intake and the cylinder heads are correct, and correctly dated for the car.

The current block casting number is 378270 with a cast date of L12. What confuses me is the engine stamp pad. It contains no VIN and the following build code FI208S. What does this "S" mean? Is this a logical replacement block for original warranty work?

[Mike E.]

Re: Block Stamp Pad Question

You have a block that was cast and assembled in December of 1962 (63 model year) that came in a 250 horsepower with powerglide passenger car.Someone either sold the original owner or you a bill of goods--it's not a over the counter replacement block.

[Joe L.]

Re: Block Stamp Pad Question

Steve-----

If you've got the engine casting number wrong and it's actually 3782870, then I completely agree with Mike---the block came from a 1963 passenger car. At that point in time, passenger car blocks like this one didn't get a VIN derivative stamping, so that's why you find no VIN. If the block casting number is actually 378270, then I don't know what you've got. I can find no record of such a block casting number.

"Theoretically", this block should work ok for your application. Compression ratio, pistons, and camshaft were about the same for both engines. The 63 block likely has a forged steel crankshaft whereas the 68 300 hp used a cast nodular iron piece. However, the 1968 block used the "large" (2.45") main bearing journals, whereas the 63 block used the "small" (2.3")journals. So, in that sense, the 63 block is inferior to the 68.

The 1963 crankshaft originally fitted to this block likely did not have the crankshaft balancer bolt tapping. So, if the original crankshaft is still installed in the block (and, has not been modified by the addition of the tapping to the snout), then your engine will lack the balancer retaining (center) bolt. Also, the 63 engine was originally designed for use with a cannister style oil filter. All 1968s had the spin-on type unit. So, if your car has the spin-on unit, then a special adapter would have to have been used to convert it. In that case, the normal 68+ oil filter adapter would not work on this block.

In any event, and as Mike mentioned, it's very likely here that someone has not told the truth about this whole situation. If a dealer had replaced the block under warranty, they would have used a Chevrolet partial engine ("short block", fitted block, or bare block). Such an engine would NOT have had the 3782870 casting number and would not have had the block stamping that yours shows. More likely, this block is a commercial rebuilder's "short block" assembly installed by someone other than a dealer under a warranty repair. It's possible that it was installed by a dealer in a NON-warranty type of repair, though.

[Verne Frantz]

Re: Block Stamp Pad Question

While it is true that this "particular" block would not have had a VIN derivitive on it, beginning with the '62 model year, passenger car engines, 300hp and above, were supposed to have the partial VIN on the pad. I have many original examples on file.
Verne.