I would use a GM also, but not a "one wire". They have special regulators in them, and there can be a delay when they start to charge, and of course they have a regulator that may be hard to get if it fails.
I would get a GM internally regulated alternator, the one I am familiar with you can buy from the parts store if you tell them you have a 79 monte carlo. It will have 3 connections. You can buy the pigtail to plug into the top of the alternator.
In the casting one of the pigtail connections will be labeled #1. Take this terminal and hook a wire to it, and run it up to the dash of your tractor. Hook this wire to one side of a small light bulb that has two wires(not grounded). Hook the other side of the light to a spot that has power when the ignition is on.
The other pigtail connection will be labeled #2. Take this wire and hook it directly to the large output stud of the alternator.
Then run a heavy(about 10 gauge or so) wire from the large output stud to the battery +.
That's it. Works great and it's easy to get replacement parts for.