Due to the popularity of the KC38r Tiger Turbo for the 7.3L, KC Turbos has made a smaller version of the turbo for those running average-size injectors. The 63mm compressor wheel has been modelled after the 366SXE compressor wheel and maintains the same profile, shape, and blade style however, it is drastically different. This 63mm wheel utilizes a larger, 7x7 wheel with extended tip technology, has thicker blades, thicker hub, thicker backing, and is reverse rotation. Combine these features and you receive a bigger, stronger wheel making it much less prone to fatigue and wheel burst. The turbine wheel has also increased in size from the old 70mm to a whopping 74mm. While they were at it, KC turbos also increased the shaft thickness from 6.4mm to 7.5mm.