I need some help with an old Dodge truck.

Neg ground good.
Test light, bat side of coil should always stay lit.
Dist side should blink with engine cranking and test light clip on bat side of coil and pointy bit on dist side of coil.
Another easy thing to do is check for an arc at points either bridging with a screwdriver or opening them if they are closed.
Breaker plate moves, the wires in there can break or short.