The weakest link in a high performance power plant is the drop gear assembly that transmits power from the engine to the transmission. This set of three gears, consisting of the primary gear, idler gear, and input gear, are of the straight-cut tooth design. These are ideal when strength is more important than the noise produced. Has 3/4" idler gear shaft to fit 1275 pre-A+ power units. See C-DROPSETA+ for same set with larger A+ idler gear. For race applications, we recommend FOR101-103 roller idler drop gear sets.