Thanks everybody (and thanks to the info).

As I said, I know next to nothing about tractors. I did a lot of research, and it seems that this engine, a Kohler K-series 10HP was in really wide use and parts are readily available for it.

Apparently, this tractor (and other tractors in this series) are really popular for pulling because they have a one piece transmission/differential that's built like an anvil. Cubs of that era were really expensive compared to the competition because they were so overbuilt.

I'll have fun getting it running,,,after that, I'll see how the mood strikes me. I might sell it to someone who can give it the proper amount of TLC, or I might just fix it up for funsies in spite of the fact that I don't have much use for a tractor.

Oh...and the dog belongs to the previous owner of the tractor! I've got enough to deal with with my geriatric Boston terrier, three snakes, a cat, and two poison dart frogs!