If the performance was down compared to the 450, what changes were made? Carbs, cams, compression ratio? You'd think it would run a little stronger with the longer stroke.
I've come across a nice 500T for $500. Haven't heard it run, but kicking it over it seems to have lots of compression, gas tank absolutely clean, etc. Should run with little or no effort. Problem is, I've also found a '78 750K I want and can't do both. Decisions, decisions.......