[jrmunn]

First, the resistance wire reduces voltage going to coil while the truck is running. This reduces coil voltage going to the points, which helps extend the life of the points. I doubt that your truck would run at all if there was a break in the wire.

I had a similar problem with intermittent running (that developed into more, but that's a long story) with my 1964 GMC 3/4 ton pickup with a 305E engine. The problem turned out to be points, which were also the last thing I changed. I think that there were only two different distributors used on these trucks. You can tell them apart by the rotor. In one case, it is a small rotor that pulls off the top of the distributor shaft (this is what I have). The other has a large, round rotor that is held on by screws. In both cases, these were common distributors and points should be easy to find. (But parts stores are most likely to sell you an adjustable set for the large rotor distributor. The small rotor points are very basic and do not have a gap adjustment screw.) If I am wrong about this, I am sure that someone on this forum will provide a correction.

If it is points, you don't necessarily have an overheating problem. It is just that the size and relative positions of these parts can shift with changing temperature. In my case, the points had burned down into the cap holding them in place. You could check this by looking, but for the small rotor distributor that I am familiar with, resetting the gap can be a real challenge if the points are disturbed or removed.

jrmunn