Here is what's up...On my just barely O/T '66 Dodge, I've been having a series of electrical woes. I fixed the voltage regulator problem I had earlier, and the alternator is putting out 12.88 VDC at idle, with 13.65 VDC @ 2,000 RPM. So far, so good... Today, I drove the car a little over 260 miles, round trip. The car started just fine, with no apparent issues. Once on the road, things were good...sorta. At speed, the ammeter showed a good charge. Once I got off the highway and the RPMs dropped, the headlights dimmed almost completely off at idle! Fortunately, I kicked the car into Neutral at the stop sign, and drove home fine. Once I got to the shop door, the car stalled and all of the lights went out completely!. I was able to restart the car, but barely. I've checked the grounds, the alternator output, battery voltage, and the other electrical connections. I have not checked the cables for resistance yet. I have new ground cables (x2). The car has been difficult to start when warmed up. So...here is where I'm at... I'm thinking the positive battery cable (original 1966 part) might finally have gone tits-up on me. I have nice, bright lights and working heater fan at speed, but it all goes away at idle; especially after a 10-mile or longer drive. I have good battery connections. Something is happening somewhere that just isn't right. Am I on track here, or do you guys have other ideas for troubleshooting this PITA problem???