Re: 1960 and 1966 lower unit swap on a 40 hp Johnson
The lower units are the same and will swap right over, but you will need to use your original drive shaft, water tubes and shift rod coupler. RDSL's came from the factory with a longer lower shift rod and a standard size coupler, so you may have to swap that out. Converted long shaft motors will have a 5 inch shift rod coupler, where as factory long shafts will have a five inch longer, lower shift rod.