I am getting 22mpg hwy out of mine with 500+HP.
16mpg towing my 34ft RV (with this much HP you don't even know it's there)
2008 1 Ton Megacab 4x4 6.7 Cummins, 2inch leveling, 35 inch tires
H&S tuner,5 inch turbo down pipe,CAT,DPF,EGR COOLER DELETED.

 

Wow after hearing all ur mpg mine really sucks!!!! 03 1500qc hemi 4x4 i think the best ive seen on my overhead is 10.8 ive had it for a bout a month now too

 

Granted I only have a 4.7L, but I average about 19-20 on the autobahn. As long as I keep my foot off the skinny pedal I am good. But I have noticed that if I leave my bed cover open (roll top) the best I could do is about 16-17.
2004 QC, 4.7L,5spd

 

My over head currently drifts from as low as 7 to up over ten. Going by the tank and calculating the mileage I can get as low as 8 or 9 if I drive around town.

And yeah mega ton. Your killing me. Haha. I'm happy to see those number come out of the 6.7 tho. AloT of people say that the early years of 3rd gen 5.9s like 03 and 04 are the only ones to get low mileage.

Besides 12valves

 

Only time a ctd is going to get better mileage than a 1500 Ram is when you facter in how much a CTD can tow, vers a gas powerd Ram.

Spending the up charge for a ctd and running arround empty will buy a hell of a lot gasoline.

Dump the 20 in getto rims and you will gain mpg as well as gain towing abillity.

Sorry that this will sound boaring, but tire psi,mid grade gas, up keep on maintance and driving just under the speed limit is going to net the best mpg gains for your buck, no matter what you drive.

My hemi 2500 is a reg cab, with a 6speed man, 373 ltd slip, on level ground, at 60 mph, in 6th gear, i'm pulling 1800 rpms, true dual ex cab high topper and I can get betwean 17 mpg to 20 mpg on the over head, I have a 35 gallon tank.

Towing over 5000 lbs drops me to arround 15 mpg on the over head, towing at my max ratiing will net me abought 13 mpg over head, any time I travel over 60 mph empty or towing, my mpg is not woorth even mentioning, when towing I do use 92 octane.

City mpg is not worth talking abought due to the low gearing in the transmisson.

A 1500 ram can't be bought any more with a man transmisson and was never a option with the 5.7 hemi in a 1500 Ram, 4.7 with 6speed man are in the 1500 quad cab, but not easy to find.

A reg cab, quad cab 4.7 with a 6speed man and 355 to 392 ltd slip in 2wd or 4wd would be my pick.

 

When I first got my truck back in 05, Drove her for a month empty, because I wanted to break it in before beating the crap out of it. W/ 3.92 gears I was getting 16 mpg. I then put the cap on and loaded her down with tools. Installed a taller tire for a bit more ground clearance in the front. Then I was down to around 9 mpg. I installed the 2500 axle w/ 4.10 and now see about 11 mpg. Scales just over 8,000 lb

05 1500 ST RCLB 4.7 6 spd manual 2wd I will not get rid of it until I can get another 1500 w/ a manual trans-looks like a long wait, but then, I own most of my vehicles for a long time. I bought it to replace my 00 DAK that was just too small. The 00 DAK replaced an 86 250 318 2wd auto with 471,000 when it blew the trans.

On a side note, I was talking to my salesman at Menards today, and he is out of his company provided Dodge, into a Ford. The Dodge was a 1996 V6 2wd auto, and had 411,000 on it and was on it's 2nd trans, original motor. He said he was getting about 15 mpg.

I guess the key is to get all the weight out.

Wish all the mfgrs would bring back the I6 W/ manual transmission 2wd truck option. Used to see a lot of em running around here, esp Fords

 

That's weird because my Hemi 5 speed auto turns about 1600-1650 RPMs at 60 and I can still only manage 16 on good day

 

I don't have mds don't know if rpms drop when in mds, I thought automatics tend to run at higher rpms than a man trans at say 60 mph or could be my tires are taller than a 1500 ram. 265 75 17 are on my truck or I don't have to gear down as much to keep my speed.

My truck is abought the same lbs as a 1500 ram quad cab.

 

sorry to post this question when your lookin for answers but what rim+ tires you have on that its sickkkkkkkkkkkkkkk!!!!!!!!

 

My wheels are dick cepek dc-1. They offer dc-2s now. Watch out tho apparently they're ghetto......

And yeah a manual would be awesome. Even a 6sp auto would be better than the trans I got. But Ill have to live with it for now

Yeah I know Diesel versions aren't. WAAAY better than the hemis but I know with programming they can be. I really doubt the trucks I've seen quoting high teens in mpgs with lifted trucks aren't all lyiijg. I'm sure some exaggerate. But still. The easier the motor can move its own weight the less stress and therefore better fuel economy. Again I know they're not 30mpg trucks. Butndef better than the hemi.