My 78 El Camino gets outstanding mileage.
All smog crap is pulled. 350/350 with 2.9 (something like this anyway) rear end gears. Edel 600 on performer intake. In town I get about 12mpg. On the highway last summer to Salem, OR, I made over 20mpg all the way down and back. Gotta love those tall gears.
- Ryan