That is a tach. I made the housing from exhaust tubing. If I had it to do over, I would have made the housing shorter and cut deeper in the dash (to allow the tach internals fit). The dash only has a hole for wiring drilled in it, so in case I decided to go back to stock it would be an easy fix. At the time I didn't have the courage to cut deeper into the dash. I now think it would look better with a shorter extension.
don
