Alternative engines for a 1980 GS550 frame

[adam01]

Hi everyone, I've recently acquired a 1980 GS550 frame which I am in the process of cleaning up and painting ready for a rebuild. I've been searching the internet for absolutely ages to see if anyone knows if any of the other GS engine's are a direct fit in the 550 frame. If anyone could answer this, I would be eternally grateful.

[Grimly]

If it's of any help, I know for a fact the GS550 engine fits almost directly into the GS(X)400 16-valver frame, so the reverse is probably true, too.

[complete cafe racer]

i have put a gsxr750 slabside engine in a gs55o frame just need to move 2 engine mounts slightly