what size BB stroker is best for race only with stock block?

I'm getting ready to lay out the plans on the BB stroker build. This will be the first BB stroker for me. Will be going into a 3,000 lb chassis. Every one builds them from 451 on up. But which is really a better size for an all out race effort? Low deck 400 or RB 440 block? I know bigger is definitely better on a street engine to make big power and keep tame. But the way I see it slinging a 4.5 stroke at the track over and over seems like your asking for block failure.. Wanting your opinions and experience. Thanks!