I have two identical 1988 Hona Preludes with the only difference being one is automatic and the other is manual. The automatic has engine problems so I want swap the engines. How hard would it be to do that, and how would I do that?

 

Why not just drive the other one that's already 5spd? haha

Anyway..

You would swap pedal assemblys probably some motor mounts (if they don't need to be hacked off and rewelded). Swap over the clutch lines/clutch master cylinder/slave cylinder. It would be best to swap out interior harness that runs behind the dash so you are prepped for the clutch switch and swapping out the auto cluster for the 5spd cluster. Swap ECUS. Check to see if axles are any different. All I can think of right now.