electrical problem

blowing just one fuse from time to time, its the one for the turnsignals, what more is that fuse connected to? could
be something shorting out to the turnsignals but i doubt thats the problem:S

also from time to time i have a run on problem with the car refusing to shut of
73duster with
340 with msd ignition

usually the connector at the bottom of the steering column. To the brake switch, then out to the lights.
Pretty common for the wire to be worn through in the trunk. Where something cuts or rubs it so it goes straight to ground.

Go to the MSD site. They have a wiring fix to install a diode for the run on problem. I can't remember exactly, but I think it goes in the alternator wiring. You will find you short to ground between the turn signal switch, the output wires to the 4 individual bulbs, or in the sockets and bulbs themselves. Turn the hazards on and wiggle the wires at each location and see if the fuse blows. It only takes a very small nick in the insulation to ground. A good visual inspection will probably locate your problem.
Doug