I have a 351 in a 79 bronco that I would like to put the Powerjection III EFI on. But before I drop $1,700 on the system, what kind of fuel economy improvement can I expect? 2mpg? I drive 98 miles r/t to work every day and would like to go with a cummins, but I'm concerned about the noise and vibration of the diesels. Anyone with experience in this department?

 

What motor do you have, the W or M? Believe it or not a carb in good tune can do just as well on fuel as EFI, have seen this many times when comparing trucks just before and just after EFI introduction in the late '80s. In general you'll get far bigger improvements in fuel economy with an overdrive transmission and/or a gearing change that brings hwy cruising rpms down to about 2000rpm.