In my 54 Dodge truck I had a 25 gal late 70s B body tank behind the rear axle that truck had a 400 mile range. My 39 Plymouth coupe had a 16 gal home made tank in the usual position, behind the rear axle, that one had a 275 mile range. My current 48 Plymouth coupe has an 18 gal tank in the normal position of the Dakota frame that is under it, it has a range of about 300 miles, which apparently isn't enough because I've ran that out 2 times in the last 2 years. Short little rides are hard on mileage.

If you get in the 150 - 200 mile range on a full tank, your butt and back will need a break about the time the gas tank will need refueling. My wife and I both need a break about every 2 hours, and a little extra fuel reserve is nice, in case the gas stations are not placed in the right locations. For me, that means a 15-18 gal tank is about right. Gene