70 Swinger Rally Dash Lights Dim

To the OP, as @340rag showed above, the bulbs you choose could be the difference. I switched to the LED's on my 71 Demon and they made a world of difference. I did not remove anything other than replace the bulbs. Now I have no issue seeing the gauges at night. I bought my bulbs off the web from "superbrightleds.com". Here are the dash bulbs I used:
1719764435533.png.

They are listed as a cool white 6500K, 110 lumen LED bulb. Dimmable and non-polarity sensitive.

Good luck!