Here's a combo off the top of my head based on what I just did with a 4 inch crank, only this one would cost less, using stock valvetrain parts.
Magnum block at 4.030, 4.25 stroke, 6.2 Hbeam sbc rods, 1.350 (?) Co pistons, 12.5 compression with a flat top piston. All this for 434 cubes. Big mutha thumper hydraulic roller, EQ heads with 2.02 intakes, bowl ported , use stock valve train, 850 and an Airgap intake . Should make 540 hp, 560 torque.
Shift at 5800, change plugs and oil for seasonal maintenance.
That is what I see as a good, stock block 4.25 stroke combo. The stock block should live fine, sure, you can say the piston side loading would be higher, but that is balanced by a lower shift point. I can see a lightened A body going 10.00 all day long and the driver is comfortable,