Those variable speed drive sheaves are hard to come by. I don't even think Bobcat is doing production runs on them anymore. I decided to do away with mine and switch to a snowmobile secondary clutch sheave system bolted together and fixed at one speed. I have a video on YouTube describing how I did it, just search Glenn Colassi Bobcat repower. As for spacing the sheaves, you'll need solid steel discs. Nuts and bolts, I'm afraid, just didn't cut the mustard for me. Even 1/2 inch stainless steel. The torque of that engine just tore right threw em' like twigs. I had a friend fabircate come steel discs for me and then I bolted the whole thing together, discs sandwiched in the middle, with 1/2 inch stainless bolts and lock nuts. I spaced the sheaves about 1.5 inches apart which is a little slow around the yard but easy on the crank shaft and plenty powerful. Variable speed drive is a luxury I can forgo; I'm just happy to have my piece up and running again. If you want more info just email me or contact me via the video. I'd be happy to send you some pictures or a video so you get an idea of what I'm talking about.