Sounds like there is something wrong with you`r 302 . I hauled my 3,300 lb maverick on a dual axel trailor in overdrive (4th gear on an AOD tranny) with my mothers 1985 E150 302/aod @ 70 mph (down shifted to 3 gear and slowed to ~ 60 - 50 depending on the size of the hill) over 200 miles no prob. When its towing the boat it will go over 90 mph (*oops I didn`t mean to go that fast) and if I`m driving sane it will get 17 mpg easy .