The 1 inch clutch market is severely lacking in diversity. Disk clutches include the Bully, Jammer Eagle, and Horstman Redhawk. Problem is, you cant find a Redhawk, regardless of what Horstman says. They will make promises but you wont get a clutch. Don't take my word for it, call them and see. The Bully and Jammer are darn fine clutches. Super strong. Problem is price. They aint cheap. Way over $400 either way you go. Way over. I like the Jammer a ton but to totally switch everything over to them would be thousands of dollars. I sold all my Horstmans after being unable to get disks or spacers. I know of 3 acceptable shoe clutches. All 3 Norams. Starr, Enforcer, and Minicup. Minicup and Enforcer must be mounted outboard. Enforcer has a "fiber" bonded to the shoes and hold very well. It will hold a 40 horse engine. Remember, for whatever reason, Noram does NOT make it in 16 tooth. 10 thru 18 driver but NO 16. Why? Who knows. The Minicup and Starr are very similar and at first glance seem to use the same shoes. They do NOT. The minicup shoes are slightly wider and IMO better. Shop around. you can get a Starr for $150ish, a Minicup for $180ish and an Enforcer for $200ish (or a disk clutch for $480ish) I like the Starr the least but if you have to run an inboard, that's the only choice. I run a crap load of laps every year on the Minicup clutch. Engines ranging in horsepower from 18 up to whatever I can get from a modified 390. I even ran one on a slicked up 440. Never have had a failure. Never seen an Enforcer crap out either. Darn fine clutches. If money is no object, go disk. I would love to outfit my stuff with Jammers or Bullys. Ill need five to start out with drivers ranging from 15 to 20. I can run stickers and fly banners and talk them up all the time. Even in victory lane. (hint hint) Good luck