How can I improve fuel economy?

[highwinger]

I know, I know, it seems futile, but from what I've read around here, I think it should be better than what it is. My last fill up was 20g/200mi...easy math 10mpg. It has been 11 recently. Shouldn't it be closer to 14mpg?

I don't know many specifics about the engine. Supposed to be a 350 crate only 7k miles on it. Some of what I know it has: double-hump heads (not sure which size), 1406 edel carb & intake, normal exhaust manifolds, flowmaster mufflers tho. TH400, 2WD 3.42 posi rear, 20x9.5" AL wheels, 30" tires. No third seat. MSD dist & CDU (no vac tho). PS PB rear AC

From what I've read:
- the double-humps are more suited for a 2 bbl -$500
- Q-jet better
- larger wheels are heavy & reduce eco - $2k
- overdrive & EFI would be no brainers - $3k ea
- pulleys not quite aligned might cause drag
- driving style is a factor

Any other suggestions on what I can check/improve? What's the best bang/buck mod? Cam? Heads?

Appreciate the help