I have a 1978 Johnson 70HP (70EL78C) with a bad lower unit. The sticky here says interchange for a 70hp long shaft is from 78-81 & 82-88. Yet when I go to Master Marine, it shows the super-cession to be 0396730 from 78-88. When I go to 1988 it drills down to the same number, but only goes backward to 1980. The only part that looks different on the two schematics is the rubber boot on the shift shaft. I have a good 1988 4 spline lower unit. Are there shift throw travel issues between these units? Will an '88 lower unit work on a 78 motor? Thanks in advance.
The chart I made was for a direct bolt on replacements. The 88 will work but the shift rod from the 78 will need to be swapped to the 88 due to shift design change on motor.