Sounds right. I used to get a free air filter once a year from Pep Boys. I would just go in to order one during their promotion using the 66 Barracuda. If they did not stock an air filter for your car you got one free. It did not matter /6, 273 2 barrel, or 273 Commando engine. They all used the same filter that year. Must have taken till early 1967 to use them all up.