Mike,

See the detailed description from Novak here: SM420

Nowhere in there does it describe a larger diameter "input" shaft. There is a note about a different spline/diameter "output" shaft and internals different in a rare number of these trannys.

I also did further checks on the web and found no other reference to an oversize SM420 input shaft.

I would say the answer would be a definitive "nah".

Dan

~ Dan
1951 Chevy 3 window 3100
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