LOL I have been hunting for clutch info all day.
All I know is that the stock clutches don't hold well - I went through 2 in my previous engine because of slippage. Of course some think that something has to slip and a slipping clutch is better than a broken axle.
This looks like the best deal.
http://forums.club4ag.com/topic.asp?TOPIC_ID=97333
Email him with a detailed description of what you have and he will set you up.
If the link is too slow here is the contact info...
(866) 327-7399 toll free number e-mail:MAXFROMMISAWA@AOL.COM
On most of the models it doesn't matter much as long as you change the flywheel and clutch as a unit. Measure the size of the parts and go from there. Note that the early big port older (EDIT: 4AF 7AF) did have a different crank/flywheel bolt pattern.