Only Autolite 1100 1v's were used originally on 1965-1966 Mustang 6 cylinder cars from the factory. In 1970, Ford started supplying Carter 1v's on Mustangs, Falcons, and other New Fords. It was the same Carter 1v carb that was used on AMC Jeeps at the time. In the Mid 1970's through the Early 1980's, The Holley 1v was used as a Ford Service Replacement Part at Ford Dealerships as it worked very well, was easily obtainable, was somewhat dependable, and did not have the Cold start issues of the Autolite 1100's and Carter 1v's. The original Ford air-cleaners did not fit the Holley 1v carbs very well or not at all. They were usually tossed or replaced with a different aircleaner. There were also height fitment problems as well, so many original air cleaners either did not fit or had to be retrofitted to work.
Tony K.