If the stage 6’s will in fact be used, along with a stock block, I’d build either a 505RB or 511B, flat top pistons, easy on parts roller cam, and it would make whatever it makes.... which should still be enough to cause some issues for the stock block.

With std port stage 6’s, I don’t feel that 700hp would be a “slam dunk” by any means, on the dyno here.

You could always swap out the top end down the road for something more suited towards bigger power numbers......if you feel that you’d like to expidite the demise of the block.