C-1 or C-2 piston identification - - Joe

[lee wassenhove]

Hope someone can help identify 327 domed casting # 3849823 STD as to its part number. We need a new or used piston for a replacement. Would also appreciate suggestions as to who might reproduce this piston. Thanks! Lee

[Joe L.]

Re: C-1 or C-2 piston identification - - Joe

lee-----

I believe that the GM #3849823 forging number was used for the GM #3850137 piston. I'm not 100% sure, but I'm pretty sure. It's academic, though; these pistons were discontinued MANY, MANY years ago.

The closest "reproduction" for this piston would be the TRW/Federal-Mogul piston L2166NF. However, this piston will produce a compression ratio of about 10.25:1 with 64 cc heads. This is a bit lower than the original pistons, but it's about the most that I'd recommend going with pump gas.

[Duke W.]

Re: C-1 or C-2 piston identification - - Joe

AFAIK the the 2166s produce the same CR everything else being the same.

The stated Spreed Pro CR is based on nominal deck heights, which will yield .025" deck clearance, but most production machined decks were high.

Also Speed Pro lists the CR using a .038" head gasket.

The GM specified CR is based on nominal deck height/clearance and a single steel shim gasket of about .018" thickness, but again, most decks were high, and then most SHP engines ended up being assembled with double gaskets to address customer detonation complaints.

I doubt if Flint EVER built an engine in that era that actually achieved the advertised CR. Like the power ratings, CR was grossly exaggerated.

With a LT-1 cam a true CR of 10.5:1 is okay for 93 PON fuel.

Duke

[Lee Wassenhove]

Re: C-1 or C-2 piston identification - - Joe

Thanks Joe and Duke! I appreciate the prompt response to my question. I was sure that you guys could advise and head me in the right direction. Lee

[Clem Z.]

what ever piston you get check the balance

against the one you removed

[Clem Z.]

what year and hp engine is your piston from

i can check to see what the orignal dome volume was and compare it to the F/M replacement

[Duke W.]

Re: what year and hp engine is your piston from

If you can find an OE spec for the compression height, post that, too.

The 2166s are 1.675" and 5.3 cc.

Duke