3.03 to T170 swap

[ThinLizzy13]

I have the oddball T170 TRS 3 speed + OD (toploader family) in my '87 F150. The trans finally gave out after 210k+ miles so I'm swapping a Mazda into the '87. I'm going to hold onto the T170 with the idea of maybe rebuilding it and putting it in my '63 in the future to get OD.
These are all very tentative plans but at first it seems like it would be a somewhat easy swap. My T170 might have the correct toploader bellhousing pattern already, the speedometer cable shouldn't be an issue, and I have the driveshaft that came with trans. The hydraulic clutch might require some finangling, I'd have to make a trans mount, and I'm not sure where the shifter would sit yet. My main concern is the input shaft.
Is the 300 I6 toploader input shaft close to a 223 I6 toploader input shaft?