A little birdi in a tree told me that Cobra heads (don't know what year) can fit and improve power wise onto a 99+ GT. Can anyone verify this claim or should I grab my BB Gun and shoot him?
There is a huge compression drop doing this. I think it brings it down to 8.0-8.5. I'm not sure you'd need a new ECU. Many people swap in 4v motors and use their GT computers -just need a custom chip. Cost Vs. performance wise I don't think it's probably worth it. You would probably be happier with porting your heads, cams, and some juice.