Autometer Boost 5776 gauge install.

Has anyone installed one of these gauges in a 96-98 cobra? Specifically, I'm trying to find a 12 volt switched power source that does not loose power when the car is cranked.. I think I've poked every wire under my dash, but so far, no luck! I've done several searches here, but haven't found an answer, forgive me if this has been covered before.
 
I have installed autometer gauges in my 96 cobra. Here is what I did, I used a test light and found one in my fuse box that was hot only when the key was backwards, crank, and run, tapped her right there for a 12V source! Good Luck :nice: