Taking It To The Track

I have a theory on it laying down at the top end.
When I use the 8th mile numbers from my time slip in the Wallace calculator, it shows 350 hp compared to the 291 when I use the quarter-mile numbers. That shows the 108 ain’t right. Wallace shows 113 when I use 350 hp.
I put a 2.5 power valve in it when I was trying to get it to idle. I’m thinking that maybe it is closing at the top end. I’m gonna run it with a vacuum gauge and take a different power valve next time.
I have to see what vacuum it has in gear. It’s only 5” in park. I’m hoping a 3.5 will work, if the pv is the problem.