Occurred to me since the last post to an older thread about Fox 35s I'd reworked, that I omitted an important development that Larry Foster and 'some guy in Georgia'

came up with.
The Hi-Zoot Crankshaft...
Why? The stock Fox 35 shaft has a very thin - by current standards - crankdisk. Even with the slight thickening on the side opposite the crankpin, it doesn't have much metal to dampen the iron piston's movement vibration. Modern designs do have thicker, occasionally massive, crankdisks to provide that kind of 'flywheel damping.'
Larry and 'that guy' developed a way to machine away a segment of the lower crankdisk, and fill it with a heavier metal. I haven't run such a shaft yet, but have heard that it is very effective at reducing vibration from this source. A good part of the way to the vibration reduction from using an aluminum piston in chromed or nickeled sleeve...
And, since 'that guy' also sells Fox 35s fitted with a CNC Backplate, his own Hemi Head, ABC S&P, AND the Hi-Zoot shaft, that combination is most likely even better.
('that guy' - if you haven't made the connection by now, is Randy Smith.

)