Stock 400 Piston Boost

The piston itself will hold up to the amount of cylinder pressure just fine. The reason NOT to use them in a boosted application is their tolerance to detonation. Has it been done? Yes of course. Can it be done? Yes of course. Should it be done? The Answer to that question comes in the form of another question. How good of a tuner are you? And can you keep the thing from rattling under boost. Any detonation at all will destroy a cast piston quickly where a forged piston would live. And yes at 6-8 psi from a roost (which is a giant heat pump) you should pull timing on pump gas. Start pulling 2 degrees per pound and tune from there.