They use 158 4watt wedge base bulbs.
Your bulb socket may not be fully seated in the gauge causing the dimness, or someone may have installed a off brand bulb.
Snaps out of the back of the the gauges.
https://www.summitracing.com/parts/vdo-600840?rrec=true
Bulbs (4 to a pack if you'd like them all to look the same)
https://www.summitracing.com/parts/vdo-600815?rrec=true
You can get these at NAPA , Autozone etc...
Red bulb boots (They go on mucho easier with squirt of isopropyl alcohol)
https://www.summitracing.com/parts/v...xoChC0QAvD_BwE
Easy access if you pull the speedo out. No need to disconnect it.