I’m needing to replace the pump on my 1986 case Ih 385. The pumps that I find say they have the “upgraded tapered shaft” and will need additional OE parts. I can’t find what “ additional OE parts” I need. I found a kit that comes with the pump and a gasket kit. I just don’t know if there is additional modifications necessary. I don’t want to get all the way into it, only to have to stop and wait for parts. Any help is greatly appreciated