Back in the day when engines had a bunch of blow by, that Marvel Mystery Oil was a great product. I used it for years until I got my first truck with fuel injection. Used to put a can in the crankcase when I'd change the oil and add a can to the gas tank about the same time.
That's a cool project, Larke. I'd sure like to see that old boy's face when you show him that tractor. That'll be a great time.

BKB