Ok lets see here... Somethin is really fuckd up. First off you need some HARD Numbers from a track, no matter what altitude because we can correct for that.
Heres an example though, I ran at a 3300elevation track and ran 13.8@100 mph... with no changes to the car I ran at almost sea level at another track and went 12.5@107. I had better track but 7mph difference! Other people report the same loss in MPH at this track so that could come into play.
Also please list IN DETAIL every part to your engine, intake, exhaust, ignition, plug gap, FP, Timing, ETC. Im sure we can find out whats wrong but you need to address all these issues first or its just guessing.
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
Going for 11's on 87 octane with A/C and 20+MPG!!!