M8 shafts are generally used on forestry mowers and large snow blowers. Transmittable horse power at 540 rpm is 91hp, at 1000 rpm 145hp.M8 SLC + FW-40. Four plate slip clutch on implement end. Min length 48". Max length 68". Tractor end 1 3/8" 21 spline. Implement end 1 3/8" six spline. Min length 40". Max length 53" 65 lb.