25mpg 71 C10. Need Your Help!

[The Youngen]

Currently doing a restore on a 71 c10 lwb. It will be my daily driver and will stay around for a long time and id much rather drive this than a compact cars so please shoot out ideas for 25 mpg. It currently has a 350 with a edelbrock 1406 carb, weiand single plane intake, turbo 350, 3.73 rear, hei, stock ride height and tires. I was thinking about going to a 200 4r but figured id go all the way. Any engine/tranny combo will work. Manual is preferable. Diesel or gas. No A/C. No tree pulling or 1/4 miles. Just a cruiser for around town. Please help me out guys. Thanks!