Max RPM on mostly stock 400?

just how far can that cast crank go? Would 700 be safe with a good set of rods and light pistons?

That is a very good question.

I myself wouldn't want to try it out at that level. I myself have not been there. I feel it best answered by the been there and done that. Application for street or strip are 2 different things as well.

You could push it on a strip only car since it see limited run time, though abusive. On a street ride, I'd be more conservitive.

Where these lines can be drawn vary with equipment and parts used. If you wanna press me for an opinion, I'd leave at, "Yea, I'd guess so." Notice how I said guess, not know so.