Originally posted by pete-tarmigan When I ordered an upper casting part from US Camera for a Manfrotto 144 tripod, they sent me the corresponding part for a Manfrotto 190 with the "190" stamped in the aluminum part and a sticker on the plastic bag specifying that it was for a 190. The internal diameter in the casting (for the centre column) in these two models is so different that you can tell at a glance that the casting is too small for a 144. Not very impressive. They refunded the cost of the order, but not my cost of shipping it back to them on the far side of the continent.
Outside of Manfrotto there are a couple of websites that specialize in Manfrotto/Bogen and other tripod parts. They have the parts diagrams so you can make sure you are ordering the right part for the right version of a tripod or head.
Years ago I called the parts guy at Bogen and he sent me parts diagrams for the various versions of the tripod and head I have. All that stuff is online now but back then it was easier (and more pleasant) to talk to a human being.