Originally Posted by
69cj
I don't have a truck but a 69 mustang with 428 cj and the best it gets with an egg under the go pedal is 13 mpg. It is stock and has never gotten any better since new.
Thats not even an apples and oranges comparison. You have an eggplant.
I have a 352FE probily recently rebuilt. That was designed to get the job done, and to pass multiple gas stations on a single fill up.
You have a 428FE Cobra Jet which was designed for racing, and winning at it. I can't remember if it was designed more for NASCAR or Hemi killing. Either way MPGS were not a design requirement.
The fact your getting 13mpg's tells me more about your tuning skills, and or driving habits.