Even a stock, 185 HP SBC, will cause traction 'problems' with an otherwise stock S30.
I've seen a very mild, very budget built, 355 do consistent 12.3's in the quarter. That's Viper territory. You could roll into the throttle in 3rd gear and both tires would spin up... at 60mph.
You'll have to decide how far you want to go with the rest of the chassis and drivetrain before you can make a decision on practical power limits. And, of course, for some people, stupid power is still not enough. Only you can decide when enough is enough.