After Market Fuel Gauge 1966 Dart?

I have a real 1966 D/Dart. Actually I have 2 of them. The one that I am working on has a 360 in it now. The guy that I bought it from had changed the tired 275 hp 273 to a 380 hp 360 back in 1999. He never had it on the road that i know of. I've had it on the road a few times, about 20 miles total, and realized it needed some repairs. So I'm repairing it.