I wasn't totally sure. I have an 86' 250 but I haven't done any rebuilds myself. I know the 85' & 86' are completely different than all later models. I just bought a pos 88' that I was parted out because the motor I sent to a builder was trashed. The whole dang thing was a nightmare. LOL it was a good learning experience for me. We need someone else to chime in and answer this cause I know they know. Heck I'll go look through some old threads and find the answers probably.