Well, welcome to the Harry Ferguson forum. A lot of tractor history belongs to Mr. Ferguson. He had perfected the three point hitch system with draft control for plowing and ground engagement and partnered with Henry Ford to build the Ford 2n and 9n series tractors. After Henry Ford the second violated his grandfatherís handshake agreement, Harry sued Ford and began building the TO series tractors in America. In 1954, I think, Harry ended up selling Ferguson to the Massey Harris company, hence the Massey Ferguson name.
Iím sure others may happily pipe in with more history.
Ps good luck with the pump, and numbers matching parts usually work.