Chasing major gremlin, hope this fixes it!

For about 6 months now my Duster race car has been plagued by missing/stumble/loss of power that starts at about 6000rpm. This problem only occurs when going down the track. I can do a burnout to 7000rpm and motor is smooth. (No, I DON'T usually burnout at that rpm)
This is a built 5.7 GenIII Hemi that is carbureted. The things I've done (that I can remember) so far are:
Jetted up/down
Fuel levels up/down (carbureted)
Advance/retard ignition
Clean out entire fuel system/filters
New fuel pump-22psi to the front, 6.5psi to the carb.
Relay for fuel pump.
New plugs
New coils
New Crank sensor
New Cam sensor
I gave up and sent the Holly 1050 Dominator back to Pro Systems. It should be returned to me this week so I can take it to the track again. Please cross your fingers for me, I used to win a lot of rounds before this happened.