I have a 94 firebird formula. I got the tranny built and have put about 10000 miles on it. Aamco built it said it was good up to 450 horse. Im not sure exactly what was put into it but they said as close as they can get to a race tranny. I think they put on a 2800 stall. I also built the motor this past summer, its 383 edelbrock heads, crower cam, 58mm throttle body, hooker longtubes into mufflex 4 inch exhaust and many other mods.

driving around town the car shifts fine, at wide open throttle it goes about 1500 rpm past shift point. If i let off throttle for a second or 2 it willl shift.
I sent programmed pcm back to pcm4less where i had it tuned in the first place they verified car should shift at 6200 rpm.

 

Same thing happened to me. I just got my PCM flashed again and its ok now. I think when i damaged my other trans it went into a certain mode to hinder it from going that high. Now mine is good. Dont know if flashing it in the car makes a difference but it fixed mine.