You might go ahead and get a serpentine belt kit for it. BIG bucks, though. It would certainly look out of place, too!
Seriously, though, it would be a good time to do a Sanden a/c compressor upgrade, which would include some of the brackets you need, I suspect. A couple of threads in here on that. Look for the more recent one by "TxDon" as he also put in the related condenser and lines, which he all did himself (with links to where he got the stuff, as I recall).
You are ALSO missing the water pump to crankshaft belt idler pulley assy. You'll see it in the illustrations in the service manual linked above.
Seems like Bouchillon Performance has the conversion kit for the power steering pump? To put the later model Saginaw (GM style pump which Chrysler started using in about 1969) power steering pump in place of the larger Chrylser-use pumps. Get the hoses, too.
Otherwise, you'll need '65-'68 parts. Many things changed in 1969 and again in 1974. Pulleys need to be for an a/c system, as the sizes/drive ratios are not the same as with a non-a/c car.
Water pump is one belt. Power steering pump is one belt. Alt and a/c compressor were two matched belts, but that might change with the Sanden kit.
Just some thoughts,
CBODY67