I know the regular AFR 225s need a 4.130" bore gasket, but what do the small bore heads need? Will a 3.910" work or is the 4.130" required still?

 

I used the stock 6.0 gaskets (4.00") from GM.

 

damn i never read anything about needed a certain size bore? i think i used a 4.060 bore size gaskets and the bore of my piston is 4.040.

 

If they're small bore heads, use small bore gaskets.

 

ONLY assuming he is running a small bore engine....which may or may not be the case. But assuming it is a 3.900 bore motor running the small bore gaskets would be prefered. We sell an .040 version Cometic if you need....

Tony

 

Thanks, Tony. It's for the 383, so it's a 3.905" bore.

As for using 4.06 on the 4.04, that's probably not hurting anything, but the chamber size for the regular 225s is bigger than the 4.06" gasket -- it's around 4.08" IIFC. So, I usually try to go by what the head wants, not necessarily matching the gasket to the engine bore, so to give the heads as much room as possible to breathe. If if it's only worth .5%, if you have enough of those .5%, you can get to 5%.

As for the eye-rolling bullshit; it wasn't some noob or it's an all-to-obvious-answer question, considering what the big bore 225s work best with. So, excSSuse me if I wanted to verify and get that date out on the board for anyone else who may look for it one day, because I had not seen any data on the small bore 225s. If I had the 225s in front of me, I would have measured. But, since I'm buying parts, I wanted to know if I could simply reuse what I have... a 3.910" Cometic.

I'll probably step up to the 4.030" for my above reasons.