My 8.0 in my 98 2500 (a 6000 pound truck) gets 10 mpg. I would like to think a smaller motor, in a lighter truck, could do better than that.......

 

Maybe. Maybe not. I have a 99 Dakota Sport 4X4 with the 5.2 and I get 15mpg driving 75 mph on the highway. I'd think the V-6 should get at least better than that.

 

Another MPG check:
05/06/24 215 miles 12.849 gallons 16.732 mpg
At 65mph, 2,000 rpm.
2003 Standard Cab 6.5' Bed 4x4 Automatic 3.92 Rear 3.9 V6

 

I get roughly 14-15 mpg with this 4.7L V8 of mine. I don't worry about mileage much anymore either since getting an EV. OP hasn't been back since day after posting this thread.

 

THAT'S HORRIBLE!! I wanted to drop in a 'warmed' 5.2/Getrag 6spd in a 88 that I got with a blown 3.9 motor. With
hopes of getting 18-20 on the highway (3.55 short bed)
I'm just getting into Mopar from Chevy, and just thought it would get decent mileage compared to say a 440.
But maybe I should just drop the 440/A833 O/D in and be done! I got a 8.25 from a '01 Cherokee that's got 3.07 gears.
A camper motor should be able to cruise at 12-1500 rpms all day long, and maybe get 15-16 with the air on!(?)