Holy smoke! Gas sipper.Most hearses came with a relatively small tanks. My '66 had a 15 gal. tank. Didn't need much more. Where were they goin? Urban driving 20 to 30 mph. Yeah, 7 to 10 mpg. But on the road, totally different. My '66 got 17 to 19 mpg loaded with tools, camping gear and towing a 2000 lb. drag boat.