depends on how crazy you want to get, how good a bodyman you are and also the theme or look your going for. I've seen the old teardrop ford lights, mustang lights, caddy lights, chevy sighns, newer chevy tails. the old caddy bullet tails. You name it I've seen or done it.
Give me some information on what look your trying to acomplish with the truck and I'll tell you what would be a great asset to it.
Lightspeed good buddy, I used to have a 4x4 '72. If your going to use those tails I'd advise you getting two sets for visability. Mount them/french them staggard beside eachother, they will look great!
If you can weld, absolutly nothing. You can get sheetmetal buckets for them the same place you get the lights. Weld them in and do some grinding and slap some filler to smooth and prime and paint and your set!
Good friend used Corvette taillamps in the stepside fenders, must have been from 70's. He used 2 on each side, one above the other tipped over on their sides. had to make a small rubber wedge spacer so they mounted correctly. I seem to remember there was some weird thing about the light socket assemblies, he bought the lights and sockets over-the-counter at the downtown Chevy dealer in Houston. had to silicone the backs of the lights where the sockets plugged in to eliminate drowning problems since on vette they are inside.
Man, they looked cool. Everywhere he went people asked him about those lights. It was about a 77 black short wb, short box 1/2ton stepside, with inline six and auto, had cragars and radials. Somebody in town is still driving it I'm sure.