Anyone ever turn an old Dart into an ultimate daily-driver?

At 8 mpg I'd be checking for fuel leaks, not leak, singular, but leaks, fuel pump and sending unit(mine was). Make sure the air is flowing, as stated, clean air filter, PCV valve. Clean fire too, coil, plugs, wire, cap and rotor. I just did a tune up on my car of plugs, wires, cap, rotor and Coil for $137.00. Upgrading from "stock replacement" to "performance"

The worst milage I have got is 13 and that is in stop and go traffic. my '73 is my daily driver, 50 miles a day round trip.

Good luck finding the time! It's wil lbe a good driver one day.