Which set of 4V heads are the better way to go 96-98 or 99-04? Also i am about to put a dohc in a gt and was wondering what little thinbgs needed to be changed or upgraded for the swap? i searched forums but not fouund good source.
96-98 are not compatible with a 99-04 intake. 16 vs 8 ports. 99-04 are better, with the 03 mach heads being touted as the best. above them are the FR500 then the cobra R/ford GT heads.
4v into a 2v requires the correct accessory brackets for the engine, cobra wire harness, intake and exhaust.
99-01 = 230CFM on the intake (flow)
03-04 DOHC (mahc 1 and cobra)= 266CFM in the intake
FR500= little better than 03-04 DOHC, not sure on flow #s
Cobra R= BEST, somewhere around 300CFM intake UNPORTED
Ford GT= reproduction of cobra Rs, shoul also be around 300CFM and about equal to the Rs.
for the money, I dont think you can beat a set of ported C heads. Even unported, guys are putting down 700+ hp to the wheels. I believe MPH built a Bullitt w/ a turbo 4v. The only thing done to it was a forged rotating assembly, and it put down 708rwhp through an auto w/ stock unported C heads