Two TDR members lately have done this:
Dodgezilla HX35/40 hybrid, drag comp, Mach 4's = 501 HP
B-1, drag comp, Mach 4's = 522 HP
Both numbers are uncorrected on a DynoJet
With Mach 4. 5's , drag comp and this turbo, you should be in that range
or higher.