No resisitor means pitted and or fried points. Remove the points and inspect for abnormal wear.
Years ago when I had my first gmc with a 270 6, the ignition switch would cut out on me. The Catholic school I went to did not teach us how to hotwire a truck, so I took an aligator clip from the battery to the the coil to ensure the engine wouldn't cut out while driving.
I made it 25 miles to work the next morning no problem. The truck wouldn't start to get home. I pulled the points and filed them down flat with some emmery cloth, gapped them with a matchstick and drove home the 25 miles. I made it home, and had to repeat the process for the next few days untill I learned I could take the hot lead to the ignition resistor. Within a week or 2, I had recieved a new switch to swap out the worn out one with.
New points are being produced in questionable places. A Pertronics Flamethrower ignitor will eliminate the points, and the need for a resistor. IMHO the Pertronics pointless ignition retrofit is worth every penny. It is also possible to modify an HEI distributor to work on the 302, or simply purchase one from the restoration parts suppliers.
