so im looking into the difference in the c heads (DOHC) from 99-01 and the 03 04 heads i know the exhaust ports are larger on the newer ones but any other key differences between them?
Some 03/04 heads have 9 spark plug threads vs 4. A set of properly ported 99/01 heads will flow just as good as a set of ported 03/04 heads. These heads need to be ported by someone who know what they are doing to really get the full potential out of them.
Try a guy on SVT performance named NA SVT. He is the go to guy now for heads/intake porting, but its not cheap.
mustang notch 4.6 4 valve
