"My heads are also the largest valved of the 3 encarnations that came from the factory."

Don't worry about valve sizes, magnums only left the factory with 1.94 1.625 valves.

There are 3 different castings of magnum heads from over the years. look it up. And the larger valves are like .002 bigger, so it isnt mouch of a difference. But yeah magnum heads do just fine out the factory door.

Hmm now MP magnum R/T iron heads would be even better