Ive got a 89 1660 and im running a 1020 17.5 head. Its got the poly slides on the bottom and the 3 inch cut case cutter bar. Im having problems with it wanting to dig in the ground at times like the automatic float stops working.and it likes to push the top layer of dirt instead of slide over it. Im always having to stop and back up. another thing it does is if you come to the top of a hill the head won't got down. It's like the floating system gets lost and don't know what to do. Then as soon as the head hits the ground again it starts floating again.