It is a Holley made for FoMoCo

It's a 600 cfm Holley 4150 carburetor that was used in 1966-1968 on 390 GT engines. It has several
different Ford numbers as it was used on both automatics and stick shift Mustangs, Fairlanes, Comets,
and Cougars in those years. The 4150 Holley has removable/replaceable jets on both the primary and
the secondary sides of the carburetor. 4160 Holleys have jets on the primary side and a plate on the
secondary side but look almost the same as a 4150 Holley.