I will attempt to post some pics here. First for instructions:
1. I ordered the tach from ebay. It is a 76 or so Jeep CJ tach. I don't think we paid more than $50.00 for it, if memory serves.
2. Once you get the tach, you have to separate the front plastic cover from the tach. Do this by using a flathead screwdriver and pair of needle nose.
3. The next step is to take the instrument panel apart. I just removed the bezel and covered the guages.
4. Take a air grinder (dremmel tool works but takes a long time) with stone attachments and start grinding the top of the hole where the clock goes. It does not take much, but some. Grind some on the two sides as well, test fitting at you go. The tach will go in front to back and should fit snug.
5. Once installed, follow the instructions provided with the Jeep tach to wire up. Very simple to wire. Don't use the light wire as you will use the dash lights instead to illuminate the tach.
Put the dash back together and that is it.
Paul