I have read a LOT of posts on this, but needed more info, so I did some research in Mr. Palm's book, page 636.
He says that a #168 or #3652, both 12V 5W incandescent, at 10mm X 30mm, will work.

I have not read anything about using Green LED's, and I would like to try 5 Green LED's to illuminate the instrument panel, speedo and tach.
I'd like to keep the green lamp covers stock, and also keep the dimmer unmodified so it will still work, but have it be a LOT brighter.

Please advise if you think these T10, #194 size LED's would work, they are also 10mm X 30mm long.
They are a lot cheaper than some of the other postings, with free shiping from CA, USA.
The cost is negligible, but I am that concerned more about the time wasted if they won't fit or will cause problems elsewhere.

Green: 6X Green SMD 5 LED 12V T10 Wedge Light Bulb Interior Instrument Panel Gauge | eBay
White 6X White SMD 5 LED 12V T10 Wedge Light Bulb Interior Instrument Panel Gauge | eBay
Blue: 6X Blue SMD 5 LED 12V T10 Wedge Light Bulb Interior Instrument Panel Gauge | eBay
Red: 6X Red SMD 5 LED 12V T10 Wedge Light Bulb Interior Instrument Panel Gauge | eBay
Amber:6X Amber SMD 5 LED 12V T10 Wedge Light Bulb Interior Instrument Panel Gauge | eBay

All: dtmmotors | eBay

 

I think these will be too bright. LEDs don't dim like an incandensent bulb will. I replaced the two bulbs in the trip computer with white and they turned out to be too bright and gave off the wrong color. Went back with green and it looked much better but they do not dim when the dash lights come on.
Look at "superbrightleds.com" They have all the sizes you would need.