Have a 90 indy 500 that runs great from 0 to wide open. If you let off the throttle and get back on it, the secondary seems to bind up. Cleaned all of the clutch but on the center shaft that is embedded in to one of the halfs it looks like some took a hammer and knicked one side of it. I know I can replace the bushings but I think it is also the Shaft. Any input would be appreciated.