Even at 500hp mild street car...if he just runs street tires and not sticky slicks or drag radials....I'll guess it'll live fine. I have a 470" stroker in my B'cuda that's north of 500hp. I run a "gasp".....8 1/4...3:73 sure grip, 4spd. It's been fine for years. The street tires give up LONG before the rear end will.