OK, a little background. I'm a former 15 year Mopar parts guy (98-12). Been around cars my whole life, dad and stepdad were techs. I really like the new hemi. Drove them a bunch at the dealer, my father in law has an 05 1500 2wd that we have put 110,000 on. Nothing but fluids and plugs for maintenance. It gets 18 mpg on his trips to Chicago and Denver from San Diego. I figure I can get 15 in my 79 Ramcharger. I'm getting 10-12 from a carbed 360 magnum with a Hughes HER0814 cam, Eddy 650avs on a M1dp. 4.56 gears, 33s and a nv4500 5spd. It's got part-time axles out of an 83. After getting 11mpg overall on a 1600 mile trip to Moab and back, NY wife is asking me to look at the costs of adding efi to the magnum vs a hemi swap. Yeah, I know such a hard choice to be forced on me.

So, it has to be CA legal which means all emissions junk. I can add obd1 now for minimal cost, already have most of it. How much better is obd2? More tunable right? That would cost me about $1500 to do right. Realistic mileage with efi on my 360 is 13-14 at best. My 95 1500 4x4 auto, 33s and 3.55s got 14. Heavier but better areo. The real unknown is how good can I do with the hemi? I do a lot if 300+mile trips for camping and wheeling. So it matters. Opinions?