Marc, all,
You are correct - it is a paddle wheel Simplicity 724 model with the H-70 motor. I did confirm a CCW rotation of the shaft which is on the left side (in operator position).
My dad (87) just hates parting with his old stuff. I have to admit - it's a beast of a machine. It (H70) threw a rod, and that was after I repaired it 2 years ago. Makes me believe there was something else wrong.
The replacement Tecumseh motor's pull starter would face front, but it wouldn't be a problem since I could pull the starter rope outwards past the machines handles.
I believe I would need a spacer block, as the H70's shaft height is higher than the replacement's - 4.125". I'm going to remove the motor on my next visit, and get the measurements. I did see the snow motor on the http://smallenginewarehouse.com site for $240. That will work, I believe.
Marc - One thing that might be a problem - the machine's belt guides are bolted to the H-70's motor area near the output shaft. Is this going to work with the new motor? What did you do?
Thanks - great forum!