MTD is using there MTD engine made in china. briggs is making snow engines, and Lauson engine, the new name for Tecumseh/LCT) has snow engines also.
My Tecumseh/Lauson/LCT distributor shows the crankshaft as NLA
Finding a replacement for your Tecumseh is going to be difficult, as your's has a double PTO, which are no longer used on today's units.
I'll be watching to see if anyone answers that request. The drive system are totally different, so I'd like to here how they did it. Good Luck.