I am sure the 4x4 headers are different, but on my 74 F350 (2wd), I had a pair of long tube Hedmans on the truck for about 12 years, only replaced them since they were looking so crusty, although when I removed them, they were still really solid, and likely would have been fine for a few more years. Since my local speed shop did not have another set of Hedmans in stock, I bought a set of Flowtechs, which fit as well, and as far as I am aware, on still on the truck, which I sold to another racer in 2014. My 390 was running the D2 heads.
Regarding the Camper Special dilema, another racer had a really nice 68 F250 Camper Special, and when he tried to install the same model of Hedmans that I had used before, they would not fit, as his CS truck had a different (Bendix?) power steering box, with a large angled "nub" sticking out of the box, that prevented the header tubes from clearing , which was not an issue with my F350, which had a Ford PS box. I had also heard some some headers would hit the front sway bar, which is different on a Camper Special, in that it bolts inside the 2 front radius rods, similar to how a Chevelle or FOX Mustang does, but on my 74, I had installed a Camper Special front sway bar, and neither the Hedmans nor FlowTechs were anywhere close to interfering.