I have a 59 Cummins diesel, it has a programmer (superchip) need to generate more hp. If I could gain fuel mileage that would be a plus as I am getting 8 mpg pulling 40' gooseneck trailer, whether I am pulling 8k or 16k lbs. I am open to any suggestions please help.

 

intake exhaust and any mileage tuner. most add about 65hp or so

 

Yeah a free flowing intake and exhaust will pick up some mileage. Also swapping out mechanical fan for some electric ones will also help mileage and power.