Well personally speaking, I would never lie about my times or horsepower, I have timeslips to prove it. I would say something is wrong with your motor or tune. Is that on the spray your losing? I got my stock motor with 160K on it to go 12.87 @ 104mph with full suspension and exhaust on 10.5" D.O.T's, it had stock untounched heads, cam, intakes, injectors, etc....
Now I have the Holley kit on a fresh 302 and with bad heads (seals and guides) and no traction I went 12.6 @ 108 on a 2.48 60ft. I don't have the compression ratio you have either I am around 9.3, so something is defintely wrong, we have very similar combos, and I am currebtly running the 3:73 not the 4:30's. With the new heads and custom cam and the additions I did this winter, I am looking for solid 11's, and it shouldn't be a problem getting there.
Tell your buddy to come up to MD and I'll show him the tail lights of a Mustang.
Now if you want some help can you give a little more info. What kind of fuel pressure and timing are you running?
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