Car sputters

[crateracer16]

Finally got on the track tonight. Car would take off until I get to 1/4 throttle then after that it would spit and sputter and pop a little, if I let off the gas a little it would want to take off a little bit. 418sbc. Msd dist with 6al box. Holley 850 carb on gas. 34*timing. I did have a few big backfires when I was trying to get a timing issue fixed a week ago. Could it have done something bad to the carb? Thanks.

[C10]

Power valve is blown possibly. Backfires will do that.

[Crash 4]

Check also for a crushed float if running brass type float, they will deform and not let the needle valve open.