I had a 79 B200 shorty van with a 318/833OD and 3.55 gears and it got 25mpg hwy all day long here in Colorado. Also a 91 B300 with 360/518 and 3.55 and it got 21mpg.
72 Satellite Sebring Plus 440, 72 Dart 5.9 4-spd, 68 Valiant, 73 W200, 78 D100 sb, 78 D200, 98 DAKOTA, . Moparmarks Parts & Restorations Desert Mopar Metal Grand Jct. CO 970-261-7039 http://moparmark.com/ motormangj@gmail.com