Increased MPG for carbs?

[Edahall]

Originally Posted by OSE_NERO

I'm still optimistic that there is something out there that can break 18mpg for us "barn doors".

Well it is possible to hit 18 mpg on a carbed truck. My 1972 GMC, 1/2 ton, 4x4, 350 cu in, did even better than that and that was in the early 80's. Here's the formula.

1. 3.08 gears
2. SM465 4 speed manual
3. P235/75/15 tires
4. SP2P Edelbrock intake manifold (small diameter intake runners)
5. Rhodes lifters
6. High lift / short duration cam
7. Quadrajet carb (leaned out for best fuel economy)
8. Carb spacer
9. Timing advanced
10. Water Injection
11. 55 mph

For even better fuel economy, I would use Vortec heads so I could run more compression and more timing advance. The Vortec heads should be good for an additional 1-2 mpg. Also, for highway driving, 2.73 gears would even be better.