If it is for a cargo van, I would say no need. I had a V-10 in an E450 that was set up as a cube van. 60mph granted us about 11.5 mpg. At 70, it was more like 9.5mpg. It is lighter that the powerstroke, but has almost as much torque. That cube had a GVW of 14050, and could clear over 5000...