Replace multiple gauges and modernize your rig at the same time. For outboards and stern drive/inboard engines. Tachs and Speedometers fit standard 3-3/8" hole, gauges fit 2-1/8" hole. Four-Gauge Outboard Set:
Guages had little or no electrical connection schematic information that was useful to me in adding guages to my boat. Perhaps a website link to more information would be helpful.
They work great and look like they belong. The only thing I don't like are the mount brackets, I would prefer a different way to mount, but it is definately worth it!