Unless you can make a set of headers or modify an existing set, I have yet to find a set that will fit without hitting the frame, steering shaft or both. I found a set of high flowing manifolds from the late 60s laying around my uncle's garage. He couldn't remember what they were off of, most likely you won't find them in the junkyard anyway. Reguardless, pretty much any manifold that hangs tightly against the block will work. Make a friend at the junkyard, they should have dozens of them laying around. Ask if you can take a few home to try and return the ones that don't fit. 66-77 Broncos seem to work well but ones with a 302 are hard to find. If you aren't allowed to take any to try just look at them on the engine, the closer to the block the better. Most will be from a car since there tends to be less room under the hood than a truck.
Matt
