67' FLYWHEEL

[William O.]

Please Identify:

1967 FLYWHEEL ID Casting number 3S56578 GM2NF DATE F237

The Box it came in: 1#3991406

[Joe L.]

Re: 67' FLYWHEEL

William-----

I think that you'll find that the casting number is 3856579. This is a 15lb, 12-3/4" nodular iron flywheel for internally balanced engines. It was originally of GM PART #3866735. Later, it became GM #3991406.

While it's USABLE for a 1967 with small block, it was not originally used for any 1967 with small block. It was used only for 1965 with L-78, 1967-69 with L-88/ZL-1, and 1970-72 ZR-1. That's it as far as Corvette PRODUCTION use goes.

Since the flywheel you have is of GM PART #3991406, that means that the date refers to 1977 or 1987. The 3991406 did not not exist yet in 1967. However, since the casting number is the same and only a 1 digit date code was used on these pieces, there's no way that anyone could discern it was not from 1967 (in case you have anyone lurking around inside your bellhousing that's real interested in dates).

[William O.]

Re: 67' FLYWHEEL

Thanks Joe:

This was in the bottom of my pile of parts that I was going to get rid of and it in a GM Box, I wanted to identy it before listing for sale.

Thanks again for the detail of information.

Bill