Should I buy it? 1963 Chrysler Imperial

I've personally witnessed my dads bone stock 64 Imp 413 4bbl Average over 15 mpg on a trip to the Carolinas through the WV mountains. Two of the tanks got over 17 mpg! My buddies two 69 new ports 383 2bbl both got 17 mph towing a small aluminum fishing boat (highway). They can be a little more efficient than most give them credit for.