I noticed that my lights get really dim when truck is a idle.When I bring idle up they brighten up.I know that is normal for generator,but I think this is worse than normal?I drove it to store today and got back in it to crank and battery was dead.Had to roll off to crank.The dash lights are flickering also.I had generator checked and it is charging.I just put a charge on battery and it is showing 6.48 volts.What kind of problem or problems have I got going on here.I also have a new battery in the truck.It is a 1952 F-1 with 239 flathead all stock.

 

If you don't have one, go buy a multimeter and check voltages at the battery.
Make sure the generator belt is not slipping.
Make sure the battery cables are heavy duty, designed to carry current required at 6 volts....Cables designed for 12 volts will not work.
1. Check static voltage across battery.
2. Check voltage across the battery with the engine running and the RPM at a couple thousand.