in the most perfect conditions i can do this with my 07 5.9 mega ctd, 3;73, 33'' tires, 6spd man, 4x4, leveled, intake, exhaust, customized smarty tnt-r tune .... goin to 35's soon, hopefully help out a bit more at hwy speeds, anything over 2000 rpms it starts dropping pretty fast

 

I can set my over head to 40mpg, long hill and cost away in N, if you did not cheat I'm impressed with your mpg.

 

thats not cheating at all, but like i said, the best conditions, thats what it does if i keep under hwy speeds, (the spd. has much lower gearing than the auto) i took it too the coast a couple weeks ago, about a 400 mile round trip, from the valley floor over the coastal range with a lot of twisty/windy roads and high elevation, and it did 19 mpg from my door and back @ just a little over half tank used, witch impressed me verry much, considering my Dak i traded in would only do about 14.2 tops on that trip

 

The cost and maintenance is not worth at all to compare mileage numbers. Even at double the mileage(with a $800tuner), it would take a couple of years to break even(unless you drove a crap load) Maintenance items cost double, so to say they go a little further..they better.
Also, as far as the oil changes, they get changed every 10kmi and require nearly 20qts! That's 4 oil changes as compared to gassers! There's no savings there at all.

4.7L's get same mpg's as the Hemi.

for overall efficiency and cost effectivness, Either a V6 or the Hemi in a 1500 reg cab 2wd will be the best bet. v6 is a little cheaper and does a little better on gas but the Hemi is easier to find parts and has a better resale.

 

its 12qts and no where near double $. well maby if you take it too a lube shop, but for a DIY its cheaper to mantain the diesel, my Dak cost me the same to service as the cummins, but the cummins goes twice as long, but thats just my expirence, everyones differes

 

Keeping it under 2000rpm is defiantly the way to go. But in an auto you gotta drive like there's an egg under the pedal. Practically hold up traffic haha. I'll do that occasionally on long trips when there's no one else on the road or whatever . Defiantly helps.

And I've heard great maintanence story's with diesels. About how they have less moving parts because of the inline 6. Yeah the parts are beefier for strength but I doubt they need replacing often. I think a properly maintained truck would last for a while. Besides maybe suspension and breaks cus of the weight

 

05 rcsb 4x4 daytona..cai.two pipe exhaust with cats..two in two out flowmaster..3.92open....city mpg 9-12. And highway mpg...15-16.8....as low as 13.9 in fog, rain, and wind

 

I'm lucky to average 11-12mpg. My next truck will definitely be a Cummins.. in a Mega Cab of coarse!!

Oh, and that's with the cap on it. Didn't change from what I can tell taking off the fiberglass tonneau and putting on the cap.