Are you wanting stock or you talking modern alternatives? The only one I'm familiar with is the stock version and the only two choices on '64 that I know of isn't the pump brand but the mounting of. They came with Eaton and one is front mounting and one is rear. I believe they show a pic of this on the autozone site but not positive. Mine is front mount, meaning the mounting bracket mounts on the front of the pump behind the pulley.