Cruise friendly low 12's with a 340 Dart

rumblefish360 said
4 inch crank stroker w/zero deck pistons and a closed chambered head, (Edel. Magnum aluminum's prefured) with a Huges or equal like cam, _ O.D. auto trans and 3.91 gear on not more than a 27 inch tire. This gear ratio in overdrive will feel like a 2.6979 ratio.

Keep the cam smallish in duration and hi on lift. (I'd look at a cam no more than 220 intake duration @ .050 an LA cam with Magnum heads would fit this bill well.) The 904 O.D. version uses less power to operate, but I wouldn't worry so much if I didn't get it and had to use the 518. The later OE tranny's are lock up tranny's and there are stall converters for these units. The lock up will add mileage.

I agree, probably gonna need a little more duration but that 220-240 mark is where you want to be.

now he said something about a turbo, i use to build alot of forced induction engines, you can definatly pull off low 12's, probably more like 11's with the proper forced induction set up with a intercooler and still get the gas milage your looking for. plumbing for a turbo is not gonna be cheap unless your a welder fabricator. supercharger store sells bolt on procharger kits, it'll cost you a little bit but it might be the best route. open up your ring end gaps on the engine you have, bolt one on and see what happens.