I just saw an old thread open up with reference to Rob's thread on the poor illumination coming from the reproduction rally-pac gauges. I thought I would share my experience.
I bought the reproduction set from The Parts Place (yes their service was terrible), with the intention of following Rob's method of increasing the illumination.
However, when I got the set, I could not figure out how to take them apart. It has been a while but I think the problem I had was the set screw for the clock.
Anyway, time was tight, so I installed the set un-modified.
The lighting was so dim I could hardly make out the fuel reading or the tach position.
So I installed some high output LED lights. They are expensive, but the gauges light up better than before. They are adjustable.
I would highly recommend them. Much easier than taking the gauges apart. You can pick pretty colours too!

Cheers, Peter

 

OK...good to know.

Check out my restore thread as I just did all 3 gauges, even beyond what Rob did.
To take tach apart, you have to bend out the tabs on the bezels front edges, just two of the 3 , and then you can squeeze the bezel retainer off. The tach clock adjuster tip doesnt come off. Its probably cemented on, so you have to paint the inner bezel with the glass on like Rob showed.

I did original Speedo and Fuel gauge too, so the bezels on OEMs are a little trickier as the metal housings are thicker to manipulate.

You got to take your time and be careful. But seems like you found a work around. Can you post a pic or two of them lighted up?