IF both engines are a Briggs, AND the crankshaft DIAMETERS AND lengths are the same You SHOULD be able to use the stack-pulley and belt from the ORIGINAL engine, and the engine should bolt right in, MIGHT have some minor wiring issues but you can get that straightened out, the stack pulley might just be a match also, better yet ! but if you're changing the brand of engine, you MIGHT open a box of headaches, POST the COMPLETE numbers from BOTH engines and I'm sure we can assist in your quest. .. :thumbsup:
Both mowers are made by MTD, ... one VERY IMPORTANT thing, ... IF you do this .... be sure to take TON'S of pic's .. they wil be immensely invaluable, as engine swaps are not in the manuals, therefore THEY become your memory and guide especially if distractions occur.