tkb289 It's about choice in some cases. In others it's about having room. In my ERA I have the originial setup from them with a Master and slave cylinder for the clutch system. A modified clutch fork is used in my car with a Lakewood bellhousing. Depending on the size of the clutch, 12.0" - 7.5" single or multi plate setup, it's also about how much pressure needs to be applied to release and have the clutch engage. The new clutches that are coming out are having a softer pedal and hold power of 800HP. Twin disc is the way to go. It has to be setup right or you will have the same problems as any other clutch. Quartertime has a lighter bellhousing then Lakewood by 20 lbs. They are having the bellhousing certified for SFI at this time. There where problem with some of the older HTBearings with leaks that would soak the clutch assembly and cause slipping and a bad smell. To the best of my knowledge this is a problem of the pass. Bleeding the HTB is the only problem I have heard of. The mastercylinder bore needs to be able to supply the slave with enough fluid to disengage the disc from the pressure plate cleanly. Your Car should have a pedal limiter as to not over extend the bearing. You can blow out the seals if extended too far. Again another mess. IMO HTB is better with less moving parts, easier if running certain bell housings, it automaticly adjusts to the clutch. If setup right will last with no maintainence for many years of driving. If you go racing that's another story.
Rick L.