Performance mixed with fuel economy!?

2005 single wheel 3500 6 spd. cummins I bought new . It reminds Me of the Torque of my old 440 4 spd. R/T. It gets anywhere from 20 up to 30 mpg depending on how you drive. Since I bought it we have been in almost every state towing a race car trailer. It now has almost 290,000 miles on it We also have the identical truck but a dual wheel. It gets only 15-20 mpg but it has twice the power after serious up grades. A little over 100,000 miles We use it for very heavy towing.

Diesels are the way to go and can be run on almost anything Home heating oil, vegetable oil and mixes, When my wife and I go to my daughters we always take the truck. 2 1/2 hour drive an the fuel needle barely moves. Our Explorer uses a 1/2 tank of gas.

The single compared to the dual wheel is this. The miles to empty readout on the overhead console when filled reads somewhere around 360 -380 on the dual wheel truck. The single wheel truck reads 620 - 640. We cannot figure it out but we use that truck due to its mileage on fuel all the time now.

The only thing I can contribute to this is since new this truck has had a tuner and has been on "Crazy larry"since. It smokes black so bad I pity the people behind me on a hill. The one day I was at an intersection on a 4 laner and when I took off the lady next to me had her window open and when I looked back she got out of her car and let the smoke clear from inside

Long story short . Power and Mileage, Buy a Diesel. To have fun and show off like I like to do , Buy a V8 gas and run race fuel mixed with Methanol or Nitro Methane and go a quarter mile at a time. LOL