Take a look in this thread. There is also a link on the 3rd page. See if it helps. There's some more truck chop chop threads, even some F-1's I think. I'll see if I can find them. http://www.ratrodsrule.com/forum/showthread.php?t=2441
measure twice and plan your cuts carefully, can look through my build also not a ford but general idea. also remember the lower you go the more cutting you have to do. might have to cut you roof in 4 pieces