I changed the snapper rolls and the gathering chains sprockets. They sale them as a kit but I had my own machined. I put on a smaller sprocket on the shaft that drives the snappers and chains. I belive it was a 30 tooth sprocket and I went to a 27 or 28. Doesn't sound like much but I picked up 1_2 mph in good corn. I left the sproket from the drive shaft the same. This made the header operate 10% faster to keep the combine at better capacity.