Chris, I'm running the 550s with 28psi fuel press (vac on) but right now I'm only at 14psi and runnin rich the whole pull, like 10.5 afr.
Not suprised I only ran 111mph in the 1/4 last nite but with a 3865lb race weight I'm happy.
Kamikaze I got the weeks in a week, and it was a full staggered set, no individuals.