Evil stang, where have you learned everything? Most people do learn from reading and book other peoples research etc. There is no way if you spent the rest of your life researching you could learn the info you can easily gain from others research. Hands on knowledge is good for 10-20% at most. Everyone w/ lots of hands on knowledge doensn't know **** from experience. I know this because I have seen it time after time. Who knows more in this whole town about building performance engines? Sorry to brag, but its me, and I have hardly any hands on exp.
Anyways, you with the slow GT40P headed motor, its not the heads. You see people trapping 105-115mph with these heads and more, you need to look into other details. What are your cam specs, whats your compressionn, do a leak down test, etc etc, make sure your timiing is really where its at. Is your balancer right. Your car is making stock power and its not the heads.
Skyler
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-1989 Saleen Mustang #406- TFS Heads, E-303, edelbrock intake,70MM TB, 73mm MAF, off road H, headers and 3chamber flows.
12.55@107mph
50-175 Nitrous Works WET Kit just added.