This project is moving slowly due to weather, other spring projects, work, honey-do tasks, etc. I've dismantled the Murray. The manual transaxle bolted right up to the Craftsman frame using the widest set of mounting holes. I had to rotate the break lever (on the transaxle) 180 degrees and invert it so that it leans to the inside. The break linkage on the Craftsman isn't long enough so I will have to elongate that. The brake system on the hydrostatic transaxle is superior in a lot of ways to that on the manual transaxle. The one on the manual unit is mounted underneath and cupped upward where it can fill with crap and catch oil leaks. The one on the hydrostatic unit is located overhead and can self clean. The brake pads are thicker on the hydrostatic unit. Odd because they are both Tecumseh Peerless.
I haven't tackled the shift linkage yet. The belt pulley on the manual unit is considerable larger so obviously the Craftsman belt isn't going to work. The Murray belt might work but I haven't gotten that far yet. The rear tires on the Craftsman are 22" versus 20" on the Murray, and that will increase speed. I have to stay with the Craftsman tires so that the cutting deck will ride level. If the increase in speed causes any power loss I may decrease the driven pulley size to match the original speed, but not until I'm sure everything else works.
Weather allowing, I'll get back on this Saturday.