Super Six fuel mileage

When I had my 69 Dart 225 w/ 904 auto, I religiously recorded my mileage. I also verified the odometer was correct, against highway mileage markers. I got a consistent 22 mpg hwy at 60 mph. Speed limits were lower then. I had a Holley 1920 1 barrel that ran a bit lean. Only mod was a Crane XR700 electronic ignition, but I recall the same mpg when I had points. If you drive faster, air drag increases as the velocity squared, so can be painful unless you shadow a semi.

The biggest problem w/ the slant six is poor fuel distribution between cylinders. I understand that the outer cylinders tend to run lean and center cylinders rich, since the fuel drops have trouble following the air flow. Anything that better atomizes the fuel before the split should help, such as carb spacers.

Don't know if a TBI would help. My Holley Projection spray appears to just hit the throttle plates and dribble in w/o much atomization. A few people have fabricated MPI slant six manifolds. That should work great if the 6 injectors are matched. A possibly easier mod I have pondered is adapting the GM CFI "spider" injector, but not sure they made for 6 cylinders.