It seems there are quite a few old Offenhauser intake manifolds for Y-blocks available, as they regularly come up one way or another on this site.. The name Offenshauser has a storied historical background. Many are aware of the connections years ago with the 1960s & earlier Indianapolis & USAC Championship racing & also USAC Sprint Car & Midget racing. Offy's were the engine to beat. Briefly, Fred Offenhauser was associated with people like Leo Goosen, the original chief designer, I believe, of the engines & even  going back to the time of Harry Miller, owner of  historical front wheel drive race cars of the 1920s or 30s.. The last of those famous engines were issued under the name Meyer-Drake.. However, to get back to the Y-block intakes, they were apparently manufactured by a company run by a younger relative of Fred, "not" the original Fred Offenhauser.. Unfortunately, the Y- Block intakes were a very simple & inferior inner design than intakes by others such as  Edelbrock, Edmonds, Fenton & others.. Before buying an Offy intake or going to considerable trouble & expense to install one, I recommend going to (or linking from here to) our moderator Ted Easton's site, where he went to some trouble to test 7 different Tri Power Y-Block intakes. In short, the Offy intake finished dead last in all the testing..  (Sorry for the error in the posting title, edit won't let me correct it)..