instrument cluster voltage limiter

I'm bringing this back for a question.

I ran the 7805 set up years ago. Never drove the car much to see how. Accurate it was. I was just happy to have the gas gauge back working.

I ordered some 7805s. Should be here in a few days.
However......

I can get a 7806 6 volt output right now. What will this do?
Make the gauge more accurate?
or make the gauge and burn it out over time?