How many CC's can I gain and any thin spots to avoid? I am swapping heads, current set are at 55CC and fully ported. The other set are around 64-65CC, will put them on my current 350 at 9 to 1. I will get a 2.07" intake valve added in place of the 2", new valve job, any guides redone and new seals installed. Don't want too high of compression but don't want a .100" head gasket either for mid 9's on my 424 ci 403 stroker.

 

Probably 3-5 ccs. Just go until any porous casting is gone. The combustion chambers are fairly thick.

 

Good 5cc will definitely help.

 

The dish in your valve as well as how far the valves are placed into the head will also give you more volume, or take away volume.......depending on how it is done and components selected.

 

Doesn't usually adding say in my example, a 2.07"intake in place of a 2" intake valve usually make the chamber a couple of CC smaller? Where as say a valve job, reusing my 1.625" exhaust valve will added a small amount of CC's. Is this correct thinking? The valve train is adjustable, so do I just buy the Milidon or similar valves for iron heads? Any other variables?