Rocker Shaft Kit, Hi-Performance/Hi-Strength. Increase the RPM potential of your engine and get more power. This rocker shaft kit helps eliminate rocker shaft side play that causes rocker arm galling, clip and washer failure. This kit includes precision ground high strength shafts, with solid steel center spacer and shims. All necessary hardware is included. Will work for all Type 1 engines, and Bus engines up thru 71. 21-2309