Why not just get the proper pulleys and bracket...
I doubt the alternator bracket will work, but I'm only familiar with the LA satyle engine and haven't worked on a poly... However the poly was nicknamed the "big block" 328, so I doubt the alternator brackets will bolt up... Same with power steering...
I'm still working on this how-to on pulleys, but there are a couple of sections that show the early LA style pulleys...