When I was having trouble with the blinkers on my '61 it turned out to be a bad ground. If you disassemble the tail light buckets you will find some clips that attatch to the body. On my truck these were so corroded that I had to replace them. My intermittent blinkers were the result of this bad ground. All I had to do to fix it was clean everything up and put new clips on. They had the clips at NAPA and they were a cheap fix! Anyways, I have super bright tail lights now...
Good luck, feel free to post more questions if I left something out.
Kyle