Modified engine crewcab gas mileage?

[Nelsonic]

I have an 89 3500 crew 4x4 with an HT 502 currently running 33s with the factory TBI and th400. I get 9 MPG. I’m about to upgrade to a ProFlo4 fuel injection and a 4l80e. Mainly to drop the rpm at highway speeds but hopefully I’ll squeeze another couple of mpg out of it.

 

[Matt69olds]

Can you tell me, PLEASE where the gas is getting cheaper..........not here in podunk Idaho!!!

Or central Indiana! Or Michigan, Ohio, or anyplace my recent travels have taken me.