My uncle used to drive a KW conventional with a V-12 Detroit and a 5 & 4(he said those air-shift trannies were for cityboys),and it'd run 85+ fully loaded all day,except for stopping for fuel,which usually used up all the time he saved going 85 & 90 all day.It sure sounded wild though;I could hear and recognize his truck from clear across town when he came through.
Speed
