The first thing my BB Chevelle did was that after 10 minutes or so of running it would shut itself off (it didn't run out of fuel). When I tried to restart it, it would crank and sound really weird but not start. Once it cooled off it could start but would shut off automatically again after a few minutes. Now it's doing it backwards. The next day when I bumped the starter it kept cranking & wouldn't stop. I had to yank the battery cable to stop it. I presume a wire is shorting out & I'm ruling the ballast resistor out but I'm not sure. For the record I have a good starter, new plugs, points, plug wires & valves set. Any knowledgeable advice would be helpful.