The 12v were generally the best for milage. But my truck in my sig gets an avg. of 17.5 around town and back and forth to work (12 miles, all back roads, 6 stop signs, 1 every other mile).
I think ANY diesel will beat your old gasser. I'm a big Dodge truck fan, and had LOTS of gasser's. Pre Magnum ('91 and older,) were not great on power OR milage. The intro of the Magnum's were alot better than the old non Magnum's. But a diesel will still be better. Especially if you're towing.
'03 Black 2500 QC/LB 4x4, 6 speed, SB3600DD, 2" lift, Raceline Raptor wheels, 305/70 Nitto's, B&W turnover, Firestone bags, HE351 turbo, 5" pipe, air intake, 2nd gen intake, BD lift pump, spin on filters, pillar boost & pyro, Pacbrake and Smarty
Last edited by Hot Stuff; 09-19-2008 at 07:40 PM.