This tube is embedded into the cylinder head making it rather difficult to remove intact. Note that the nut and ferrule assembly is made of two pieces, with the ferrule being a compression fitting used to secure the smog tubes to a series of ports on the cylinder head.
Sold individually, 8 total needed for smog installation. Application is 1967 - 1970 390, 427. 428CJ engines. In 1975 Ford started making these out of stainless steel. Tube dimensions 5/16" O.D. x 1.960" long. C6AZ-9A484-C