Check that both crankshafts are the same diameter and length and that the connectors on the wires coming from under the flywheel are the same. If everything checks out you should be good to go.

The 28 series engine will have a 1" by 3-5/32"(?) crankshaft as will the 25 UNLESS the 25 is turned down to 7/8" on the end which I don't think it will on a JD. The 28 will have an extra bolt with accompanying casting protrusion on the back in the middle of the crankcase but again, I don't think there will be an interference problem. The stators will interchange IF need be.

Walt Conner