I'm not sure what the RPM's are. He had 2.6's in both holes and told me it was overrevving by about 300, so I asked Turk about it and he said to put 3.1's in both holes, so I changed all the rivets and my friend claimed it didn't even change it, which is impossible I know. So then I put 4.5's in all holes for him. Well now he says it's better but still not right (he's trying to get it at 7800). I really don't know what the deal is with it. My friend isn't a complete moron or anything and has screwed with snowmobile clutching quite a bit so I don't know what to think. His mother just died on Saturday though, so his snowmobile is the last thing on his mind right now. Once we get more snow and he's doing better I'm sure we'll be screwing with it some more. I wasn't trying to hijack your thread or anything like that. Hopefully someone will answer your question.