FLAPS is Favorite Local Auto Parts Store. Napa should have the old style wires. May have to ask for some for an older six cylinder tractor.

Parts Plus stores should have metal core plug wires, and I'll see about the part number in the morning. I'm not sure about the copper part though. Jeggs and Summitt Racing would be a good place to look.

Unless you're wanting to be a purist, the new plug wires work fine on these old stovebolts. Less radio noise too if you're lucky enough to have one.