1-1/8" x 4-5/16" shaft, tapped 7/16" with 1/4" keyway Kohler Vertical 26 HP 7000 Pro Series Engine 747cc Please measure your old engine crankshaft, as Kohler makes 1 x 3-5/32, 1-1/8 x 3-5/32, 1-1/8 x 3.94, 1-1/8 x 4-5/16 Mounting holes are drilled only. Recommended to use nut and bolt or the self-tapping bolts from your existing equipment Kohler KT745-3096 26hp 747cc 7000 Pro Series V-Twin Engine with 1-1/8-Inch by 4-5/16 crankshaft