CY Engine Code Mystery Block

[Bob B.]

Hi all,

I got a 1960 engine a few years ago and it has the pad stamp shown in the picture. The pad has a CY engine code, which is the for the aluminum head hydraulic cam FI engine. The guy I bought it from said nothing about the CY and said he'd blown the engine in his 1960 back in the '60s and replaced it with the one I bought. Decades later, he saw his old engine in a hot rod and bought it back.

The block has been machined, and the stamping is not completely standard, but anyone faking the pad would not likely have stamped it like that, so I'm wondering if it could have been Corvette engineering? I am no expert in stampings, but the F, 4, and C are dead on, the open four being less common, but identical to when it was used, so someone at least had good stamps. The VIN and date/code stampings both look like they were done in a gang. There is a J at the beginning, smaller and offset down. And the 5 is stamped over something else.

The F404CY should be F0404CY for normal production. And the 4905 VIN is March 14, 1960, before the engine date. Anyone faking the CY would have made a lot of mistakes, and it seems anyone faking an aluminum head engine would have faked the higher HP CZ instead. So, I'm not sure why anyone would have put it on like this for any reason, unless it was Corvette engineering.

Anyone else have any other ideas?

Thanks,

Bob

[Patrick B.]

Re: CY Engine Code Mystery Block

The problem with it is that the block has rotary machining marks which were not done at Flint, and all the stamping was done with individual hand stamps. The Flint engine plant would have used gang stamps, and I believe the VIN is late enough that St. Louis would also be using gang stamps. Why anyone would stamp this with a rare engine code and a date later than the car build is a good question, but the simplest explanation is that the stamper did not understand engine codes.

[Dennis C.]

Re: CY Engine Code Mystery Block

Hi Bob,

I have to agree with all points made by Patrick. I think it would be an up hill battle to have aluminum heads accepted on a '60 and that stamp pad doesn't help at all.

Dennis

[Jim D.]

Re: CY Engine Code Mystery Block

Nothing about that stamp pad looks original.