Other Chevy cylinder head castings would do in a pinch ... As such, allotting excessive time to porting and polishing surfaces in the valve throats or intake and exhaust port runners cut into ...

As an example, if the valve seat on a small-block Chevy iron head is 2.02-inches ... time you find you are about to pocket port a set of cylinder heads. The post Tech 101: The 90-Percent Rule ...