HEY SPENCER the fuel tank is suppossed to 21.9 gal 86-91 dsl and gas 2 and 4 dr , and one other point i might add to z-mack and kravada (sorry if i got your name wrong), when you fill up , let it set for about 30 sec or so , so the foaming will go down as it has a tendancy to kick the pump off , the bigger the tank the worse it seems to effect them, hey Zmack i can go you one better on the milage boast, my 71 dodge 1 ton van with the 440 magnum and dual fuel tanks (70) gal total will go an astronomical 700 miles , lordy for a dsl in that thing, i can live with out the acceleration but sure would love to get around 20.mpg, it gets the same milage sitting still as it does going 70 towing a trailer ,filling this thing up will weaken a credit card it just goes limp,, take care guys Jerry