i think the low finishing #'s is motivation to build a rig that will finish. this is the type of race that is gonna test you, if it were easy either no-one would do it or everyone and their dog would do it.
i had a 76 with a single gas tank clear at the back of the bed. the main fuel pump was close to where you had yours and it had another one just behind the cab up by the frame. thats how it was when i got it and it worked fine.