The H70-130176F has a 1"x 3" shaft. The newer style engines have a thicker mounting base. If you have studs for mounting, you may have to knock them out and use longer bolts to mount the engine. If you have any other model of engine, you may have a different shaft size. If you buy an engine with a 3/4" or 7/8" shaft, you will need to buy the sleeve kit for it also.

Additional Info

A customer said that this he has an older unit that has 3 to 4" clearance between the control chute rod and the engine and that the control chute rod arm can be adjusted for more clearance. Due to this information you should be able to use the wider overhead valve engines. The pulley looks large enough to be able to use a shorter shaft and use a bolt and washer to thread into the end of the shaft to hold the pulley on.