Dash bulbs - Radio ground

Radio is chassis grounded as is everything in the car. Only 1 ground wire to battery so everything is grounding through that wire, and the engine block, and chassis ground strap at firewall, and all the little hardware that holds things together.
Bulb I use is Sylvania #2825. Slightly brighter than OEM, long life. 5/8 bulb sockets available on HELP parts line in most part stores, ebay, etc...
NAPA Echlin ( spelt ) brand may be a higher quality socket but costs more of course.