Mercruiser 140 pre-alpha and alpha one upper gearcase compatibility

[dancewithme951]

Just rebuilt 1973 Mercruiser 140. Engine running great but I now find the outdrive upper gercase is shot. I have a working Alpha one 1.84 upper gearcase (would swap the shorter yoke shaft from the original "R" /pre-alpha upper gearcase with the longer one on the Alpha one) and was wondering if I swapout will I encounter shift linkage issues with the Alpha one upper unit? Any other compatibility issues when mounting to that pre-Alpha gimbal hosing?

 

[Bt Doctur]

how many splines are on the lower driveshaft? If you have the coarse (8 spline) ,only a coarse spline will swap. You cannot swap a 13 spline for an 8 spline

 

[dancewithme951]

Lower driveshaft compatibility not an issue.