I dunno. I have heard claims for longer than the Magnum version has been around of guys that get "around" or at least "close to" 20 mpg from a 360. I don't care if carbd, LA, Magnum, TBI, or multi port EFI, I have NEVER been able to get close to that. In my experience a 360 is a 12-13 mpg motor/ no matter what body its in, in town, on the highway, towing, not towing, cruise control on or not, flat land or hills, Ive had several. Most recent (current as well) 01 Durango, part time 4wd is same as every other 360 Ive ever had in that department,
ONE TIME we took a trip from IL to Houston area, TX and back and it surprised me. Been on many such road trips since. No different MPG, than when my wife drives it thru town 11 miles each way to work and back, same MPG. the 360 is and has always just been a gas sucking pig.