I had the cluster out of my 86td to repair the Temp Gauge and figured "why not"... The stock dash lights are pretty dim - kinda hard to read the trip odo, or fuel gauge.
Most home-improvement stores have 12V strip LEDs, you can get them for cheap online too. (Auto shops seem to charge more.)
They can be trimmed to short lengths, in sets of three emitters:
Some new holes in the top of the cluster to line up with the emitters:
Gaffer's tape holds the strips flat to the cluster:
Hot-glue holds the wires so they don't pull on the flimsy PWB:
Bright enough now, at full intensity
They dim just like the stock bulbs:
I don't intend to run them full-blast, except when checking the trip odo, or at dusk when it requires higher than normal brightness.