If you want a reliable redio, the least expensive idea is to have your original radio restored. Those old filter and paper capacitors need to be replaced as they are notoriously prone to fail. Cost shouldn't be too much especially since it is still working and your lucky you have someone in the area that can work on them. I'm going through mine myself and need to order the plastic bits too. Can you share more about what is wrong with repro parts you bought and where you got them so I can try somewhere else? Likely all the vendors buy from the same source though.
My truck is converted to 12V so I need to deal with that issue. Rather than run a dropping resistor to the radio, I'm converting the radio to run on 12V. You can replace the tubes, vibrator, and bulbs with 12V equivalents. The vibrator transformer needs to be switched to a 12V part too. Here is a neat trick, the '53-'55 Buick radios are similar to Chevy but ran on 12V. The Buick transformer fits the Chevy radio perfectly and allows it to run on 12V and still look, sound, and feel original. Buick radios are easy to find cheap to salvage parts from.
-Ed
