Here is an interesting article, by Hagerty, about the race-ready (not for street use) factory specials that were produced in the early 60s. Like the 1966 Coronet and Plymouth Belvedere A990 sedans that were powered by the 426. Unlike the tamer street Hemi cars that hit the showrooms, it used a racing version of the 426 with aluminum heads, 12.5:1 compression and twin Holley four-barrels on a magnesium intake manifold. Louder, Lighter, Faster: Detroit's Early-'60s Drag Wars - Hagerty Media
By definition, a sedan can be a 2 or 4-door automobile that seats four or more persons and usually has a permanent top.
AI for once is accurate on this, and I quote: No, not all sedans have four doors. While the term "sedan" is often associated with a four-door vehicle, it's not a strict requirement. Some sedans can have two doors, though this is less common. Traditionally, the term "coupe" is used for two-door vehicles, while "sedan" refers to four-door vehicles. However, the automotive industry has blurred these lines, with some manufacturers offering four-door "coupes" and some two-door "sedans". The word 'Coupe" is an anglizized form of the word "coupé" (pronounced "Coop-eh" which is the past tense of "coup" or "cut" in French. In other words, a larger car cut short.
BUT, a "hardtop" is short for "Hardtop convertible" which means that when you roll down all the windows, there are NO pillars from the A pillar to the B pillar, which is the rear roof pillar, such as on the gorgeous 1971 Roadrunner AND Charger. I used to rolll all my windows down and enjoy the beauty AND unrestricted view provided in mine. Some four-door cars were 4-door hardtops. https://www.curbsideclassic.com/aut...lamorous-four-door-hardtops-part-2-1960-1964/ They wanted to do this with the new Challenger, but it took adding too much extra weight to give the roof adequate rollover protection to enable this, so the blacked-out pillar behind the side glass that joins with a sturdy roof arch hidden by the roof pad is a lighter way to make the roof strong enough.
