Old 70's Garden Tractor

Anyone know much about one of these. The one on top is the one I found, but all the others are look alike tractors to give a better idea, since I only took one pic of it. It has a 15hp cast iron horizontal shaft engine, 4 speed sears suburban style transaxle, and what looks like it used to have the 3 point hitch.
So far I found out it's a 1972 mtd product made with many model names like caterpillar, fifteenhundred, and farm king. On numbers all I can find out is 990 or 960. A guy has it for $500 and I'm going to try to get it for a project tractor. Hopefully a yanmar clone swap sometime and some beffy tires. Some good info would be helpful and some ideas.

Its yellow!