You're basically building a 440.
Any 440 with Stealth heads should be able to make 400-425hp falling out of bed. In other words, a Comp XE268 will probably do it. Don't believe me? Go back on this board and see what Fast68 did with one. But to get the "loopy" idle you need a different cam, either the Hughes smaller Whiplash or the Comp Thumper. Hughes says maximum compression ratio is 10.0:1 so that's what you build the engine to. If the piston requires some sort of a dish, be sure to use a piston with a "D-shaped" or "Inverted dome" dish.

I think you're looking at 450hp or maybe more.

R.