Race car mystery-Help us solve PLEASE

does the engine sound the same?

"last run zach said something happened at the far side of the track that run"

could be something silly like a plug wire grounding out, or bad ign box, rev limiter, fuel starvation (fuel pump has a short) etc.

i'm guessing electrical, second choice would be cam timing / chain
third guess would be one cam lobe / rocker or pushrod.

you could put fresh plugs in, take a few passes and compare all 8 that might help