We run the head mount on a few cars for the vaccum canister so I do not think that is a issue, but worth a try. You need a in car vacuum gauge to see whats its doing down track. I havent drained my vacuum canister in over a month and 75 runs.
There is no reason for you to run a 41 nozzel IMO, dynos always like more fuel, drop that to a 40 and I'd be shocked if it didnt run faster again.
I am same CI with more power and have no where near that much fuel, mine would be a slug with that much fuel.
Did I read right your water temp was 220 degrees after a run ?
Your gaining ground but from the dyno #'s I seen I thought it'd be a 7.70s player.