Put em on a magnum block, they are stronger than any stock LA blocks ever were and there is 550-600 hp 340 blocks surviving

It would not live up to the heads potential but it beats full ported RPMs that seem to stop around 600 in serious effort engines. The victor would just be getting started.

To help with the 59* lifter issue I prefer a higher ratio rocker to straighten the lifter/PR angle slightly and access flow faster. It is a small crutch for a *59 engine but the shallower valve angle is going to help also by tilting the top of the valve away from the intake.

Of course my favorite option is to stuff a 4.25 crank in there to bring the RPM down.