I would gather it would have been a much bigger issue in the carbed engines. The old F-150 and the early taxis weren't designed with a whole lot of thought to air flow at the best of times, anyhow. I wouldn't want excessive restriction in a modern engine, either, but filters will last a lot longer than we give them credit for. On older carbed engines, you could really notice it in the farming sector at harvest. Heck, there were times when the engine would choke out altogether.
