As you can see in the above photos, the '55, 223 and 272 engines had the front air dam stamped into the top of the air-cleaner main housing. The air-cleaners for these in 1956 had a separate piece of tin bent at a right angle and formed to the radius at the top and resistance welded on to the top rather than having the dam stamped into the top. Aside from that, the '55 &'56 2bbl air-cleaners were not interchangeable, since the '55 Ford EBU and Holley 2100 carbs had a slightly smaller air-horn throat than did the '56 Holley 2110.
the 4bbl air-cleaner for the teapot carb was a different animal that had a pig-snout at the front for intake air.
Then there was the T-bird air-cleaner which was the fourth different design. It had a very low profile due to the T-bird being a more compact car.
I never payed much attention to the F100 Pickup trucks. They may have had a completely different design from these and may have had different color paint from the full-size car models.