In 1974, when I bought my first car (69 Road Runner), the carb went bad and I went to buy a new one, the replacement, or so I was told at the dealer, was a Holley carb. That's what they gave me. Now I did see plenty of 71's come from the factory with a Holley. I'm sure that many earlier ones had Holleys as replacements in the years after they were bought. My 71 GTX, 440 4bbl, was definately a Carter from the factory. My 71 Road Runner, had a Holley from the factory.