Best magnum MPG?
A quadrajet is 10x the carb of a thermoturd and not made of plastic. They will get better than a 1406 but still a carb. Put the FI back on and you will get much better mpg. As far as all the Dakota/Durango talk, bet most of you are still running crap plugs gaped at .035". Upgrading ignition like our upgrade kit will typically result in 2-3 mpg and run much better.
What a Dak or Dur will pull on road has no comparison with an A body, they weigh 1500# more , are 4wd which sucks power and the hood is taller than the roof of A body. While an A body is no Triumph TR-7 wedge, it is much closer than the Dodge truck profiles which are pretty much a sheet of plywood at speed. That will make a huge diff in wind drag which is what kills mpg.
Like I stated earlier, I actually have checked mpg in a 71 Swinger with 5.2 Mag FI and OD AT, it got 25 on hwy cruising at 75+. close to 20 in town. It got 18 in Dak with AT on hwy, I know this because it was a buddys truck and when it got clipped by red light runner, I bought it from insurance co. 18 to 25 is a 30% improvement just from swapping bodys....