Below is a writeup of my swap from standard lights to LED dash lights. My temp gauge light died, so I decided that, while I had the dash apart I would try LEDs. I only replaced the backlights (to try and get the dash brighter) and left standard lights for the oil idiot light, driving lights, high beams, and low on gas.
I got my lights from http://www.superbrightleds.com and they were a 5 element, about 80 lumen part (part number 194-CW5-CBT cool white). They were $3.95 per bulb - here is the receipt:
Note - most of my lights were 194 (I think) but my clock had a different light (per below). I checked my parts box and my old tach had lights similar to my clock. So, you should look at your gauges to see what type of lights they use before ordering parts. I had to do special (non-destructive) wiring for the clock and one light on my tach. The rest of the lights were plug and play. Note that the lights were not as snug as the originals, and one light fell into my speedo and I couldn't recover it - $4 down the drain.
Now for before and after pictures. I used the same camera, lens, aperture, shutter and ISO speed for all pictures. This should give you a true apples to apples comparison. For each gauge, the first picture is "before", the second picture is "after" - going from left to right on the dash. Note the car was not running at the time (my lights get brighter once the motor is 1000+ RPMs). The dash was "max bright" with the rheostat fully clockwise.
Gas Before:
Gas After:
Tach Before (only had one backlight):
Tach After (with two backlights):
Temp After (no before shot because the light was burned out when I started the project):
Speedo Before:
Speedo After:
Clock Before:
Clock After:
Full Dash Before:
Full Dash After:
Verdict and thoughts: My dash wasn't that bad to begin with. But it's noticeably brighter now (and can still be dimmed). The color is more blue and less yellow than original, but still looks good to my eyes - newer rather than vintage. The green light on the speedo and the set up of the tach make those two gauges look like they have different lights from the other three gauges.
Bottom line: I don't think this mod is for everyone. While the gaugues are brighter, I used 80 lumen bulbs ($4 each) but going with 100 lumen bulbs (at $6 each) would be even better. The fact that not all the gauges have the same "tone" may bother some and may make it look less than professional. I spent about $35 and had to do a bit of creative soldering and wiring - I plan on leaving the LEDs in because the dash is noticeably brighter.
Let me know if you have any questions.
Peace out.
