4v head swap
 

Hey guys im new here, but im looking to get some info. I have an 03 GT - I want to know what all is invovled in swaping in some 4v heads. What year(s) cobra's heads would be compatible with my bottom end. I know I would need a new intake. Anyone with experience in these matters, your input is greatly appreciated.

i 2nd this

I believe all Cobra heads are compatible w/ the GT bottom end, however, a lot of parts are needed. Intake manifold, timing cover, cylinder heads, timing chains (I think they are a different size), tenioners, a computer from a Cobra, valve covers, cooling system, throtle body, valvetrain (if it didn't come w/ the heads), and possible notch your pistons. Now, I am not an expert on this topic, I'm just simply naming all the parts that are different from the SOHC. Personally, I think it would be much cheaper to just buy a Cobra engine and computer and to just swap out the GT engine. The latter would be better since the Cobra blocks are stronger.

You'll have to extend some wiring and you can use your GT computer, you'll just need a tune for it, which would be a good thing anyways.

I’ve heard you’ll need the heads of course, intake upper and lower maching the year of the heads….. everything else except computer is the same…..as far as size goes… the timing chains appear to be the same length and go on only one of the cams then there is a secondary chain that goes to the intake cam, from the exhaust cam.