I had a new 1965 Sport Fury in 1965. It had a 318 and AC. Made a few trips between Detroit and LA area. It was great on gas. I finally changed the 2bbl setup to a Carter AFB by using an earlier intake (1958 I think), had dual exhaust made up, and was very happy with the increase in performance. I didn't do it, but changing the 2.76 gear to a 3.23 would probably make a huge difference all by itself.