I gotta chime in here. I drive my 49 every day. There is nothing wrong with a six volt system. My truck has the original wiring harness. I have put liquid electrical tape on some bare spots( this was all on the head light wires) and run a new wire form the ignition switch to the coil. I replaced the hot lead from the battery with a new correct cable. I'm using the original ground straps, just cleaned all the connections. The voltage regulator has been replaced and I took both the gen and the regulator to a local auto electric and paid $5 to have them bench tested. the gen was fine, the reg was shot. It starts every time including after long runs in 98 degree heat followed by a 20 minute heat soak. Check each piece in the system and you WILL find the problem. My .02.
Dave
