Guys thanks for the replys. I will check into what's available through the dealer. Aaron, if you look at SDMan's axial flow history I think he said in 86_87 they switched to the 3 blade design. I can sure tell in heavy weeds or grass on mine that the 4 blade sure slows the crop down and really makes the e ears bark. Yes you are also right, the speed is critical. The previous owner tried running a faster speed and it broke chains, slowed it down and it stopped. Good chating with you. P.S. Disrupters are in, now getting my serrated bars milled so I can lower them down to the proper distance from the lug on the disrupter. Andy