Wellllll...ya kinda got to narrow that down a bit. 580/700 and 610/820 are two very different types of engines!
580/700 are typically fed from the bottom of the crankcase and I don't see many options there! Some of the the 700's used a reed cage type set up whereas the 580's used a typical plate set up.
The 820's can be configured many different ways...what are you trying to do?
You need exhausts for both type engines? The 580/700 had a different design than the 610/820. Let me know. I have a client that has made some repopped units and I can see if he has any right now.