Fel-pro 60273 ?

The thicker the gasket, the better the insulating factor from intake heat. But in the NHRA/IHRA Stock classes, we are allowed to run 2 factory-type gaskets. I guess I'll need to ask around and see if they have a "spec" thickness for them.

On a somewhat similar note, in the early years of IHRA Crate Motor Stock, they were checking the thickness of 1" spacers that were allowed under the carbs. It turned out that some manufacturers sell spacers that are a bit thicker than the advertised 1"!