Instrument panel bulbs
My 74 Dart had a few of the sockets broken and the bulbs weren't making good contact, therefore not lighting up. Go to Advance Auto and look for "CALTERM (08523) Instrument Panel Socket" for the socket. I think it came with two replacement sockets in the package. It fits 5/8" instrument panel socket holes. Advance Auto part 5473136. Should be around $3.00 per package.
I checked my original 74 owners manual. The speedo/instrument bulbs were #158. I think the 158s have been replaced by 194s. Sylvania makes a box of ten 194 bulbs (Sylvania part #34761). Advance Auto part 5081602. Again about $3.00 per box a couple years back.
If you don't have an Advance Auto, call Calterm in Milwaukee, WI at (800) 228-5123.