These inlet rocker arm kits by Competition Distributing have a different from the stock inlet levers ratio. This allows the intake valves to open wider and therefore more gas/air mixture can flow in. The location of the pivot bolts in the brackets for the inlet levers are matched to the changed ratio. All components are made entirely of chrome-moly steel and are case hardened to resist wear. The inlet levers feature oil-impregnated bronze bushings, hardware made from high-grade steel, flexloc nuts and pre-installed grease nipples. They fit 1915-1929 Harley-Davidsons, but the larger pushrod adjusting screws for 1928-1929 models must be used.