I used the Superbrites website. You can input your vehicle year etc. and they will give you the recommended bulb for every application. My original dash bulbs were #57's so they recommended, and I used:
BA9s LED Bulb - 5 SMD LED Tower - BA9s Bulb and I used the blue color. Haven't really checked them out at night to see what they look like. Maybe tonight.
As for the Tach, I did run a ground direct from the battery, no difference. I emailed the Autometer people and got a response asking me a couple questions, which I answered. But have not gotten a second response. Must have him puzzled too.
Paul
On Sunday, January 5, 2020 at 4:52:00 PM UTC-6, Paul L. http://1962to1965mopar.ornocar.org/ml-le wrote:
While I'm working on my dash and bulkhead connector wiring. I'd like to improve the dash light illumination. Mine is so poor I can barely read the gauges at night. I replaced the rheostat a few years ago. Not sure of the quality as there are dead spots in it while turning it trying to find the best setting. But have any of you upgraded the dash bulbs? Are the LED's available. I plan to check for all of the usual culprits like bad grounds or low voltage etc. And speaking of voltage, do I remember correctly that the voltage from the dash voltage regulator is 5 volts?
TIA Paul L.