Nope, the MPH shows what kind of power you're making. FWIW, My car weighs almost exactly the same and my stroker runs 117.8 in the 1/4...but I make nowhere near 620+ hp. My converter flashes to 5000 and I shift at 6000...if I shift at 6500 it runs the same number (strokers make big flat torque curves...and most are at max hp by 6000-6500.)
Without your combo, all I can do is guess...which is what I'm currently doing.