400 stroker cranks

I know it doesn't take a big crank to make big HP and torque on pump gas. It wouldn't be hard to order a 4.25 kit (512) and run with it BUT minus having to buy custom pistons and maybe adding about another 175.00 to cut the counter weights on the crank and some added cost to balance the overall price will be the same. The big issue I see will be the block work to get it to fit.
I don't have the heads to support over 750HP and if I keep the revs low the weakest point should only be the webbing over the crank.
I am in no way an expert and I know this maybe considered wilder build because of the stock block and not the hp level but I have been running researching for weeks and the part prices are the same or not that much more.
If I am crazy please let me know.