4A series engines normally run a T40 (4 Speed) or T50 (5 Speed) gearbox
3K/4K/5K series engines run a K40 (4 Speed) or K50 (5 Speed) gearbox
T40/T50 compared to K40/K50 are like apples to oranges, different splines, lengths etc etc. only way you would fit a K series engine to a 4A series engine is with an adaptor that is near impossible to find and yes, you also need to run the A series gearbox x-member..