I know this topic has been covered a bunch of times. I didnt have a /6 then,but now I do. I just got back from about a 100 mile little jaunt and at last fill up I calculated 19.36 MPG.

In town I am calculating about 12 MPG.
How does that measure up?

These numbers come from a Slant 6 in a 1972 Dart Swinger Special with a 3 speed manual and 3.23 gears in the Rearend.

Sounds about right. My old 74 Dart sport with granny gears and a 904 got 25mpg (CDN, so about 20 or so to the US gallon) on a 100 mile trip which was about 90% highway driving. And that slant was tired and had BAD blowby.

Sounds about right. They were not a 30 MPG engine.

Sheldon

had one in a 84 pickup with a manual overdrive, 75 mph on highway, never got over 14, worse in town, had to run about 55 on highway to pull 18

22-24 for mine, highway driving...178,000 original miles and very tired.

My 83 D-150 slant 6 overdrive 4 speed truck, just got 17.13 mpg out of the latest fill up of 87 octane.

I tossed the lean burn computer and installed an electronic distributor and ecu, and junked the smog Holley one barrel in favor of a rebuilt 65 Carter BBS one barrel.

those 3.23's are going to help you around town(the low torque needs help) & hurt you on the highway(eng buzzing too high). unless you're a traveling salesman most people spend more time than they think(when asked) around town rather than the interstate.

Had a few slant A bodies in the past and remembering being slightly disappointed in their mileage. I was a teenager and drove like a teenager but they were all less than 20 mpg.

Presently have a 65 Belvedere with a slant. It's an automatic with 2.94 gears. Around town is over 20mpg. Best tank was 26mpg.

Our last long trip was to the Mopar Nats. It does not feel like it gets good mileage since at 70 mph it requires about 1/2 throttle. Which BTW is 20mph away from it's top speed. However that trip surprisingly gave us 25mpg.

All stock expect for a Pertronix ignition module and manifold vacuum advance.