15.0 mpg to 21.6 mpg!

7milesout said

I don't think my engine would idle AT ALL at 14.7 AFR. And when I ignore that AFR gauge and set idle based on the Edelbrock manual, I wind up in the 13.0 range anyway.

WOT
12.8:1 - Lean best torque
12.2:1 - Mean best torque
11.76:1 - Rich best torque
11.01:1 - Fastest flame speed in cylinder

Right out of the Edelbrock carb manual below. The table below compared with the numbers above is what I'm shooting for.

View attachment 1715094711

Click to expand...

I found that their tables are ok for generalization, but not all motors run the same, or want exactly the same.
My own motor runs around 14.5 at idle with a light lean lope, 13.5 mid throttle cruise and 11.5-12 at WOT.
I'm going to go a little leaner on the WOT eventually, but I spend so little time there I'm not in any hurry to do it.

It's not a race car and spends most of it's time around 1,500-2,500 RPM's
Normal driving around my shifts are in the 2-2.5k range.
On the hiway at 80mph I get a little over 25mpg running at 2,100 RPM's but that is because of the 42RHOD and 2.73 rear gears.
Also running a 600, but the electric choke version on a mild built 5.9 Magnum.
When I had the 318 and 3 speed 904 I got right at 17 at 80mph.