^^^ Agreed.

Put a set of headers and a good flowing exhaust system on it, bump the timing up a touch, and stay out of the skinny pedal. Anything else is going to be a giant waste of money and time to try and gain MPGs. You would NEVER get your money back. You would be lucky to even get your money back from the headers alone.

 

Slight to moderate increases in fuel milage can be had. Providing your modify the system correctly. Is it worth the amount of money you have to spend to get that extra 2 or 3 mpg. Not really. Things I've done to mine were costly but power came up a bit and milage very little. Speed density system, f3 heads ported, 2.11 1.66 valves, custom ground on blank cam with 114 lsa, block decked to .003 out of the hole. Intake ported new stroker 502 rotating assembly. Air horns removed,long tube headers free flowing muffler single in dual out. Timing set at 12 degrees, new plugs and wires msd coil. Alot of money plenty of power to spare, just not worth it if you want better milage. No one ever buys a 460 for fuel milage.

 

Do what these guys did and see if you can beat them or verify the findings.

FOUR WHEELER Magazine's Project M.P.G.

 

No one buys a 1 ton dually for mileage period. Doesn't matter what engine it has.