Call St.Clair Wilkerson in Embro, i belive the phone number is 519-475-4332, ask to talk with John, the owner or Rob the Service Manager, both these guys really know their combines inside out, great guys to deal with and bend over backwards to help you out, after you get it done you will wonder how you ever did without this change. It was like night and day for us and we were even considering switching colors both our 500 and 800 heads were terrible from the factory, this really works well, you won't be dissappointed.