Just to talk to the fat girl at the dance, I'll strike up a conversation. I'm going to bet it only delivers 3 more MPG. B-body, C-body, A-body, I'll bet it doesn't matter. I say that based on my 84 Crew Cab long bed dually, auto, 4:10 gears. I get 6 to 7 mpg; empty, towing, trailer empty...