SPEC is a good clutch with lots of options for you to choose from.
I, on the other hand run Superior Clutch. It's a custom 9 puck, sprung, Kevlar/ Copper setup. I also had a while ago a custom pressure plate with double-row diaphragm....my clutch/ pressure plate combo can withstand 380ft/tq !...overkill for what I have right now...:lol:
Your best bet would be, go with Kevlar (even though it chatters...:evil: )...maybe 4 pucks, sprung (if you like to have that smooth engagement)...otherwise, if you want on-off operation, go without the un-sprung.
So, again, either way: Superior Clutch or SPEC are really good clutches, and both of them give you the ability to fully custom make your own clutch/ diaphragm based on your needs.
Call Superior Clutch and talk to Robin at: (408)436-1189 and tell him your problem, he'll be able to help you out...:waytogo:
Superior Clutch is located in San Jose CA....so the turn-around shouldn't be too bad....