I agree with 66birdman I also have had multiple problems with old Ballast Resistors I really like "Accel #150351 Dual Ceramic Resistor around $12" have currently on a 79 Ford Pro Mud Truck and 1984 Charger Bass boat 140 chevy 4 banger and soon my 62 GMC.
You can run a jumper straight from the battery to the positive on the coil to test if the truck will run........BE VERY CAREFUL.... The coil will overheat and blow its top

Been there done that. Remember Testing only be quick and disconnect connection asap!!!!