Ignition switch failure

The ignition swich on my 69 Satellite has failed again. It fails on the run position. The switch is only 3 months old. This time it failed at idle and the engine just quit. The last time it was at 60 MPH and took out both mufflers. I have checked and cleaned the switch connection and the connection at the firewall. The ballast resitor has been changed. My father owned this same vehicle back in the 70's and I recall the swich being changed at least once or twice back then. When I restored the car, the 318 was removed and replaced with a 440. It has a new Summit distributer and coil. When the restoration was done, all electrical connections were cleaned. I can not figure out what is killing these switches. The amp meter shows a normal charge and the voltmeter shows between 14 and 14.5 when running. I would think that if something is drawing hard enough to burn up these switches that I would have indications of problems elsewhere. Are these switches known for failure? I think these were used for one year only. I would like to cause of these failures before I have to add a relay in the system to save on $60 switches.
Author: fivepoint