Not to try and turn you down or anything, but I'm just going to make a suggestion. Personally I would only go about doing something like this with a hydrostatic machine because if working with a manual, you have to figure out how to mount the clutch to the engine. IMHO it would be easier to just make/buy an adapter for a drive hub for the hydro driveshaft than to try and figure out how to mount a clutch drive plate to it. That being said,
I'm sure it can be done. I'm interested to see how this project turns out
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'70 107 with k301 engine swap
'71 106 with 38" deck
'70 147
R with factory replacement k321, 42" deck
'61 Original with 38" timed deck
'63 70 "pinkie"
1863 with 54" deck
'46 Farmall H, '50 Farmall Cub
105 x2 (parts)