Hi,
I had the same problem and after surfing around a bit found a number of references pointing to the best solution being to add two extra lights in the back of the speedo and rev counter, see for example here ( http://www.spacecitypanteras.c...ing_Tech-Session.htm ). So I pulled them both out of the car, carefully dismantled them and then it is very easy to see where there is space to drill two extra holes to take two bulb holders. I also did an extra thing and used a silver paint pen and painted the inside canted edge of the black 'reflector' to help reflect more light out. These modifications made an enormous difference, and solved my problems.
Cheers, Tim.
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