That's the original GM design for these describblers.
It fastens to the engine pretty much like any other. There is a clamp with a bolt on it.
Installation instructions can be found in the 1948-1952 FSM on page 12-29. Not sure what page it is on in the 1954 manual.
1950 Chevrolet 3100 (Ol' Roy)
1939 Packard Standard Eight Coupe (The Phantom) | 1956 Cadillac Coupe de Ville (The Bismarck) | 1964 Ford Galaxie 500 coupe |1966 Ford Mustang (Little Red) | 1969 Pontiac GTO (The Dishpit) I 1979 Ford F-100 | 1976 Ford F-150 (Big Red) | 1995 Ford F-150 (Newt)
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