Good day;

Do any of y'all out there have both engines in service on different F150s and/or both F150 and F250 trucks in service? I am attempting to determine the difference in fuel mileage between the 4.6L and the 5.4L when running on CNG.

According to the EPA, the 2007 F150 gasoline engine fuel efficiency numbers work out to 13/18 (4.6L) vs. 13/17 (5.4L). Is that about the same way it works out for the F250 (5.4L) vs the F150 (w/ the 4.6L V8)?

I don't really need the F250's payload capacity on a regular basis, but if the mileage stays that close with a CNG conversion, a longer stake bed would be nice.

Thanks neighbors,