Be wary of listed cfm ratings, if they dont list the machine and how much H20 and how much lift. But also its my understanding that FORD GT heads are much more involved, require a custom intake and are insanely expensive to start with and to get the kind of cfm your talking about is big labor $.

Ford GT rated
294.6 CFM @ .550" Intake
245 CFM @ .550" Exhaust

03-04 Cobra heads
233 CFM @ .500" intake
168 CFM @ .500" Exhaust

 

http://forums.corral.net/forums/show....php?t=1026790 - they claim 350 can be had from FGT heads

They arn't showing the actual results, but its pretty close. I would guess they are reading 10 or so cfm on the high side based on what other have done. For the $ navi heads or 3v are your best bet IMO.

 

http://www.hennesseyperformancestore.com/gt700.html - give some idea what to expect... based on the numbers it seems pretty close

 

I think that the OP is just gonna stick with the TFS heads and the custom turbo cams and put the rest of the money towards making the car look SICK!!!

 

There is a whole different issue of what is a safe port job...

 

Couldn't agree more

 

More questions..

1. How to dyno a C4 since it's a 3 speed tranny? I mean is it possible?
2. The car already has Weld racing wheels (15" I think) which is ugly as hell!!! ;( Does slicks tires comes in various sizes like 17"?

Thanks!

 

They do, but they dont have the sidewall to hook like they would on a 15" wheel. The 3rd gear in the C4 is a 1:1 ratio so you dyno it in 3rd. But here are some 15" wheels that i would LOVE to have...

http://www.summitracing.com/parts/WLD-796B-510208/

And then find the matching front runners. They will look sexy on your silver car. Also, look into some actual slicks instead of those drag radials that it has on it.

 

Thanks Teej but I was looking for something like SVT Cobra wheels.. or some kind of aftermarket..
Any website for a slicks tires?