6.4 Hemi Trucks
My truck is a 2014 ram 3500 diesel high output dually set up for towing with 4:10 gears and average is 16-18, I towed my 67 dart home when I bought it and with the car in the open trailer and the bed full of parts I barely even felt it back there, plus my average was about 15.8 still towing. If your towing my .02 is a diesel all the way, I've towed with both gas and diesel and prefer diesel.