The inner (smaller part) is different between the 2bl and 4bl engines and the outer is the same for both engines. These are for 72/73 applications as the 71 was different. These were sourced from 72-74 Full size Ford and Gran Torino 351c and 400 engines. As bkdunha suggested, if your going concourse or you just want your car as close to the way it left the assembly plant, these are a power buy from Omie01. Many were tossed over the years or just simply rusted away. If they'd fit my 71's I'd snap them up now!
Vinnie, 73pony is correct on the right side only application. Only dual snorkel air cleaners such as the 82-85 5.0 "HO" engines would have a "Heat Stove" and air cleaner duct on the left side.
