Gary Spitznogle , 319-766-2665, probably has some of these NOS parts, or can tell where to look for them. You need to take the pistons out and see what you need. When you take the rod caps off, keep the shims in order, so that you can get them back in the same place they came out. I try to have an equal number of shims on each side of the rod, and you will want to adjust the clearance properly going back together. Headwork can be done by your local automotive machine shop, you will probably need to supply the parts, I am working on a Rowcrop, same tractor basically, just earlier. Amazingly, it required no parts, I took it apart and the valves and guides didn't show any wear what so ever, my guess is it was rebuilt and set until it stuck. Sometimes you can luck out. While you have the head in the shop, you might want to get hardened exhaust valve seats installed, that way you can run unleaded without an additive, simplifies things a little. You could change engines if you want, that would probably give a unmatched casting number, or you might want to talk to Gary about rebuilding yours. He does some of that on the side, and is good at it, but he does take his time, so, don't expect instant gratification. As far as your carb, and mag, I wrote some articles on these rebuilds in the magazine a few years ago, the carb should be an Ensign, and the mag an American Bosch, unless it is the later version with the impulse in the mag, that was a different setup. Contact our editor, Chris Losey, he might have some back issues available, with these Tech Tips in them, it will give you simple step by step instructions on the rebuild of these units, as well as a source for parts. Good Luck!!
Have a great day!!!
Andy