If you were clipping the rev limiter @6400....... going 124mph.....28”...... 3.54’s.
Driveshaft rpm should be about 5250.

At 6400, the engine is turning 22% more rpm than the driveshaft.

Or was the misfiring in high gear at the traps more of a tuning issue?

Sounds like more tuning req’d......and more track time to get a handle on what’s going on.