More pictures of the mounts you have in the first picture could help. Second pic, Not for a 72 truck with a 318. Bolt spacing for engine block attachment is 2 inches, if there more, then they're big block. Passenger side, width is 3 1/8 inch and a somewhat centered mount hole. Driver side is 2 7/8 long and the mount hole favors the front of the mount, for a 318. Driver side attaches to the block behind the lugs, passenger side attaches to the block in front of the mount hole lugs.