1971 Dodge D-100 pickup. It had a 360ci V8 from a '79 Ramcharger. 4 speed towing transmission--1st gear was actually "granny gear", and was too low to actually use in normal driving, so it was essentially a 3 spd.
Dual exhaust with small glasspacks...I could (and often did) set off car alarms with it.
It had awesome torque and was a handful to drive. I never really calculated it, but I estimate that it got about 8mpg!
Sold it off before I came in the USAF, and haven't seen it since. I don't think I even have a picture of the old dog.