1972 GMC rear end help

[90four5spd]

Hello everyone. I recently purchased a 1972 GMC project truck that the rear end is very noisy , even at low speeds. There are several pull-your-part type places around here that have many 73-86 trucks I could pick up a cheap rear end from, but need help with what rear ends would work without having to weld new spring perches/shock mounts. I did use the search button, but had no luck with finding the information I'm looking for. Any help would be appreciated. Thank you!