C2/ Engine casting numbers

[Glenn Ochs]

Real dilemma here.... I recently became a member of NCRS and ordered the information manual for a 1967 Corvette. About six months ago I purchased a 1967 L71 convertible that was established to be a numbers matching original engine car. After looking over the engine section, I find reference to the engine casting number 3916321 being only for the last 100 or so 1967's. With my serial number being #7S120909 and with the above block I am worried if I got it again(1962 Corvette... another story). Anyway, any help with the line between the 1967 #3904351 and the 1967 #3916321 block usage dates would truly be appreciated. The information on my engine/car is as follows.

CAR SERIAL # 194677S120909

ENGINE CASTING 3916321

CASTING DATE D277

ENGINE PAD TO525JE 7120909

BUILD DATE K14

BODY NUMBER S8742

CYL HEADS 3919840

I believe this thing is original, but reading the NCRS manual has me concerned. What do you folks think? Thank you in advance.

[Joe L.]

Re: C2/ Engine casting numbers

Glenn-----

All the numbers look ok to me; I wouldn't question the authenticity of the engine based upon the "numbers" and "dates". The block was cast on April 27, 1967 and the engine was assembled on May 25, 1967. That's kind of a long interval, but such an interval is not uncommon.

The car's body was finished on June 14, 1967. So, the engine assembly date is just about right for the body. Now, none of this is to say that the engine actually is original to the car, but nothing would indicate to the contrary.

Now, for the other side of the coin: the '321' block is generally considered to be a 1968 block. Also, it uses a spin-on oil filter. Does yours have a spin-on filter? I really doubt that the factory would have converted this block using an aftermarket-type adapter (GM never used such a piece in PRODUCTION and, as far as I know, never offered such a piece in SERVICE for converting cannister-style blocks to spin-on). So, if it's a spin-on oil filter, then I could see it being factory (even though 67s are not generally thought of as using the spin-on filter). If it's a cannister-style, I'd be more suspicious that a conversion occurred somewhere outside the factory.

One other thing: the '321' is a fairly rare block. If someone were going to try to "make up" a 67 L71, I would think that they would have a lot easier time finding the generally accepted '351' block than a correctly dated '321'. Also, the dates on your block are really too early for a 68 model year useage. So, if it wasn't used on a 68, then it must have been used on a 67.

[Lane Ockerman]

Re: C2/ Engine casting numbers

Hi Glenn,
According to Spec Guide:
Casting Date is April 27, 67
Pad Stamp is May 25....."JE" is 427 / 435 hp...."12909" is Late June, 67
Build Date K14 is June 14
All of these #'s seem to add up.

I show the casting # should be 3916321 ??
I show the cylinder head # should be 3904391 ??

Hope this helps some.
Lane #38102

[Glenn Ochs]

Re: C2/ Engine casting numbers

Thank you folks very much. I fell a ton better about it all. I got the impression from the manual there was almost no chance of a 67 with the 321 block. I checked today, the oil filter is a true spin-on and the 3/4 square plug is just above it. The numbers on the engine pad look just like those shown in M.F. Dobbins fact book. I'll keep going with my top flight objectives from here. Glenn