Magnum 5.9 Magnum Rebuild: What can You get away with?

I think I would call RHS to make sure they are machined for 8mm valves of the same length as the magnums and not assume they will work.

People refer to 8mm and 5/16" when it comes to valve diameters interchangelby but an 8mm is .315" and a 5/16 is .312".