All the cat secondary's are pretty much the same since the early 80's. The bear cat secondary is going to be bigger so its geared down it will work but you have to change everything so don't get one of them. The other zrt's up to 97 will fit but there not a roller clutch. Even the zr's up to 98 will work but not a roller clutch 97 zr 580 EFI had a different secondary only for one year it looks like a polaris secondary. The 97 zr 440 was the first year of the roller secondary clutch. The out side roller part is whats different it will work its almost the same as what is spose to be on it. By 98 cat put roller clutches on everything. The sleds with the diamond drive secondary are going to be different there smaller around because of the gear drive in the chain case it will NOT work any secondary off a diamond drive sled on a chain case sled. I think in that all the roller diver covers will pretty much fit. I would say if you can find a secondary clutch 2000 and up you should be fine. Whats wrong with your secondary how is it wore out?? The bushings bad. I think you can buy the bushing that rides on the sleave at a dealer and have them press it in.