I have a 1967 Shelby GT350 that has an electrical problem I cannot figure out.  At idle the car shows no charge on the amp guage and as long as I drive it during the day a battery will last several years. But whenever I turn on the headlights, or hit the brakes, or use the turn signals the car shows about a 10-12 amp discharge.  I have replaced the alternator, swapped out several voltage regulators, checked the ground on the voltage regulator, replaced the solenoid and the problem persists.  Someone suggested the light switch may be causing my problem, I am in the process of getting a new one.  Any thing else I should check???  It's getting darker earlier now and I want to attend some cruise nights but can't right now because of the drain using the headlights.  Help!!!