You can pretty much change anything, with the exception of injectors and cam, on your motor without affecting the computer. If you jump up to 24 lb injectors (or larger) the computer doesn't know it and is still operating them as if they were 19 lbs and you'll lose power. The biggest thing you have to worry about with a speeddensity set up is your cam. It must keep the correct vaccum for the SD to work correctly. That's the only phone number that I can find for Cam Motion and they don't have a website. They are located in California but I don't remember exactly where. I believe a custom flat tappet cam from them runs around $150 or so. Around $290-300 for a custom roller cam. Now Crane makes a pretty good flat tappet cam called the Lightning cam (made specifically for us GEN 1 guys). It used to basically be the Ford B351 cam. The part number for it is #444232. Comp Cams makes one, too, and it seems to be a bit better cam as well. The Comp Cams part number is #35-255-5 (grind # FW XE254H-14). Also you might check out
this link which might have some more information you could use on your 351W. It's a GEN 1 Lightning FAQ page but it might help you figure some stuff out for your bronco.