1973 Dart Swinger Gas mileage

7milesout said

17 is good. I've got a 72 Scamp with a 360 / 727, 24" tires on 14" wheels, with a 600 CFM Edelbrock 4 barrel. Holding it to 55 - 60 mph (2,800 - 3,000 rpm) I can now get about 17.5 - 18.0 mpg. That took a lot of tuning to get to that. And I'm putt-putt-putting down the interstate.

So, you're doing good. Spend money elsewhere (my $0.02).


7milesout

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That calculates out to 3.55s in the back.
Same as I had in in the early 2000s. With slightly taller tires I was doing 2600 at 56 mph, for 65=2870. Yur right it took a lotta tuning, even with my nearly 11/1 engine. I finally got tired of putt-putting and stuck an A833od with a GVod behind it. Final drive in double od was 1.97:1 so 65=1600, a reduction in rpm of 45%. According to the 50% rule my mpg shoudda jumped up 22.5%. According to that ,the 3.55s shouldda been returning 24mpgs......... but I never saw that.
I did see a tad more than what you got, probably due to the manual trans. They say a manual is good for 2 mpgs but I never ran that combo as an auto so can't say.
At 2800/3000, I feel for you man. My current combo is at 65=2240, just right for the now bigger 230*@.050 cam. But this 230 is really hard on fuel, and there is nothing I can do about it..
Good job on the 17.5/18