I've got a 2001 3500 8.1 w/ Allison Iand 212,000 miles 've done k&n intake w/ granitelli mass air flow sensor, diablosport tuner, put dual 3in dynomax mufflers into a single 4 in exhaust out the back . I'm not really concerened with mileage cause the truck only gets driven maybe once a week with a 30 ft. Goose neck on it. Just trying to find out what I wanna do to it next just to help it out while towing . Any suggestions???????

 

Cam swap and headers. They make some grate torque cams

 

you want it to tow? dual 2.5 exhaust if it has cats get rid of them, and a tune