Now that my '72 Dart is finally on the road, I have noticed absolutely abysmal fuel consumption. I suppose I shouldn't be surprised because big cams are not known for economy, but still...

It's a 451 with a slightly reground Mini-Express (.652, 272@.050). 10.3 compression. 4780-2 double pumper with a Quick Fuel 12-700 baseplate, converted to 4-corner idle and adjustable orifices. I'm still adjusting and trying different settings but at the moment it has 70/78 jets and an 8.5 PV driving .053 PVCR.

Idles at 1200 rpm, 8" vacuum, 13:1 AFR on the gauge. Highway cruise 14-15:1 at 60 mph (3000 rpm, 3.91 gears, A833) and 14" vacuum. Tends to go over-rich with the whole t-slot flowing before the mains come on (12:1 at low speed moderate throttle). Idle timing is 27 degrees, slow centrifugal advance to about 35 degrees at high rpm, plus a vacuum advance can (to ported vacuum). Goes to around 48 degrees revving in neutral.

It's a reasonable estimate but I used at least 5 gallons of 93 pump alcohol-free, and have 21.9 miles on the odometer (correct speedo gear)
No, it's not leaking anywhere or blowing black smoke...

Now that does includes a lot of idling, throttle winging, and heavy pedal application on the back roads up to 40 mph and 4000 rpm, and a few miles on the highway doing 50-80 blasts.

Many years ago I had an A-body with a basically stock 383 except for .484 purple cam, DP-4B, 750 vac sec, A-833 and 3.23 rear. Averaged around 12 mpg mixed, could get 15 highway if I stayed at 60 mph, and my worst tank was all stop & go 1/4 mile at a time, 8.3 mpg.

So I would like to know what kind of fuel consumption others with big cams (who actually bother to measure) are getting.
Thanks.