Cylinder head dyno shoot out

If the build plan involves a roller cam stout enough to put the power level into the mid-500 mark, that’s going to require a fairly stout set of springs.
The type of springs that aren’t easily retrofitted onto oe or (especially)magnum heads.

I know if I were doing the test, it just wouldn’t happen.

The argument that “most people” are swapping from oe heads to aftermarket is one I don’t necessarily agree with.
Particularly if the build is a stroker making over 500hp.
Imo, these are more often than not fresh builds that will be getting new heads right from the start.