nice you wanna put sled pulleys on an i/c engine. get you a magnetic angle finder (hf has them) measure the length of the tapers. and a mic for diameter. you will probably have to change the weights/rollers and the spring on the driven due to less power.
I relies the internal changes but I was thinking more on the line of the polaris quad 4 strokes. Polaris diesels might me close to the rpm of a ungoverned Industrial engine.
Sled PTO is typically 30mm with a 10:1 taper. In other words, it starts out as a 30mm straight shaft then for every 10mm of travel down the shaft the OD is reduced 1mm.
Yea good luck finding a sled driver that will fit any industrial engines pto. If your looking for cheap torque converters, i thibk some golf cart cvts will work. IIRC raywelder on here is using a golf cart driven on his 18 twin motorcycle.