I bought a 25 ft sea devil with twin 1.6 omc. One motor has rebuilt bubbleback with five hours on it the other had bad powerhead. So I bought a 78 evinrude 115 just for the powerhead, compression is good 115 all the way around. Used my carbs intake ignition flywheel. The only problem I had was the shift throttle cables. So I made a bracket used two precast threaded holes and mounted to block. Works fine. I was under the impression that 78 to I think 88 was the block I needed to do this. The more I read the only difference is the mounting point for the shifter/thorttle cables, is this true.