1966 small block cylinder case casting number

[Jim C.]

Hey C2 Experts,

I have a VERY VERY late 1966 small block (327/300). I believe its motor, trim tag, and VIN tag are original to the car. The stamp pad appears to be original and correct. My car is about 120 cars away from the end of the 1966 model year. The current NCRS Judging Manual (p. 60) says, "The casting number for most 327 engines is 3858174. Casting number 3892657 is possible on very late cars. However, to date this is not verified." The casting number on my motor clearly reads 3892657. My question is whether any one has seen another ORIGINAL 1966 small block with the 3892657 casting number? Does any one own such a car? I'm trying to find out when 3892657 cylinder cases started going into 1966 small block Corvettes and if these blocks were continued through the end of the 1966 model year. Thanks for any info you guys can provide.

Jim C.

[David D.]

Re: 1966 small block cylinder case casting number

Jim, The 657 blocks started showing up around serial number 26800, but was not used exclusively. Dave

[Jim C.]

Re: 1966 small block cylinder case casting number

Dave,

Thanks for the info. Is there any documentation regarding this? An NCRS article, etc? If you're familiar with this information, why does the NCRS Judging Manual still say "not verified"? Have you ever seen another small block motor like this? Thanks again.

Jim

[David D.]

Re: 1966 small block cylinder case casting number

Jim, I don't know if there is any documentation or a NCRS article on this, or not. In about the same time frame, the 351 block started showing up in some big block cars, that is also a "not verified" block usage, according to the NCRS Judging Manual. I have not "personally" seen a late car with the 357 block, but others have, at least 2 or 3 original documented cars. I think the main reason you see "not verified" in the NCRS Judging Manual, is because the judges have not seen enough (don't know what criteria is used) original documented cars to be certain. It is a rather small serial number range (less than 1000 cars)from the end of the 1966 Model Year, plus the 357 block not being used on all late SB cars, would make it a tough call. I do know the majority of these 357 blocks were cast in June of 1966 with engine assembly in very late June to mid-July/1966 time frame (but most were assembled July 6, 8, 11 and 14th). It was also not limited to just 300 HP engines, as it was also used for 350 HP. Maybe others can add more info to this. Hope this helps. Dave

[Jim C.]

Re: 1966 small block cylinder case casting number

Dave,

Thanks again.

Jim