This engine has a 1-1/8" x 2-3/4" shaft. If you use the CH740-0124 please note it has a 1-1/8" x 4" shaft. The shaft is not hardened steel and is drilled and tapped 2" deep. You can cut the shaft down to your size or use spacers. There may be minor differences like wiring, air breather, throttle and choke controls, however parts should be interchangeable as needed.