C2: 327 block ID

[David Hicks]

I have someone who has a block, and I am trying to help him identify it a little better.

He claims it is the following 1963-327(383) corvette motor with 521 duel stage cam, roller rockers, 9.5to1, 30 over, casting number 3782870, 2 bolt main, 202heads. The heads are not stock and he can't find any other numbers on it other than H25 stamped at the back of the block.

Would this actually be a 63? If H25 is the cast date, that would imply it is actually a 65. Can anyone help me identify this one further.

Thanks

[Jack H.]

Re: C2: 327 block ID

First, only the suffix code on stamp pad identifies a 'Corvette' motor. The casting number (870 in this case) simply says the cylinder case is a generic 327 engine. The same casting was used in Chevy passenger cars and trucks. I can't tell you how many times I hear the refrain, "I've got a Corvette engine!" just because the block casting number agrees with that used in Corvette....

Once the cylinder case was cast, it's the secondary operations (build) that lead to making the raw block become a Corvette engine (pistons, crank, cylinder heads, intake, Etc.). As these operations progressed, the engine assy plant 'wacked' the stamp pad (portion that protrudes from below the front of the RH cylinder head) with an identifying sequence. The last letters of the sequence (the suffix code) pointed to a bona fide Corvette engine.

After mid 1960, a second set of numbers were stamped into this pad at the car's final assy line. These are a sub-set of the VIN number the engine was installed in. This is called a VIN derivative.

On the rear pad (where the bellhousing bolts), you'll find both the SB block cast number as well as the cast date. In this case you say 'H 2 5'. That would translate into the Hth month (September), the 2nd day of the month and 1965. The presense of a single year digit, identifies the block as being cast in Saginaw and, most likely, assembled at the Flint engine plant (correct for a Corvette SB, but MANY other car/truck assy plants got their engines from this source too).

Last, as of 1965, the '870 block was still used for 327 Corvette engines. So, the proof of whether or not the engine originally was a 'Corvette' motor lies in the suffix code on the block's stamp pad--would have been an H? sequence with the ? indicating the exact motor configuration (base car, 300 HP, FI, Etc.).