I decided to finally resolve an issue that I first wondered about as a kid: did the new for-1956 Cadillac 4-door hardtop use the same roof pressing as the existing 2-door hardtop? It wasn’t as quick and easy as I initially expecte. The big challenge was finding two shots from as close to the same angle as possible.
I know there are some purists here who are offended by the term “four door coupe”, but these 1956 four door hardtops were essentially a four door version of the existing two door hardtop coupes. Essentially, or actually? Did the four door use the exact same roof as the two door?
Don’t let the bright trim molding on the lower edge of the two-door roof throw you; it was applied to the roof, so the real lower edge is at the bottom of that, as you can see at the top of the front side vent window.
Taking measurements on two different images is precarious, even if they appear perfectly lined up well like these two. Eeven the slightest difference in camera angle and lens type can cause subtle but surprising distortions. I wasted too much time trying that approach until I found the obvious and definitive answer to the question. I’m sure some of you will too.
Purely as a frame of reference, here’s the sedan version, which of course has a totally different roof as well as a shorter tail. The hardtop roof is also lower, by over two inches. It certainly changes the visual impact considerably.
Update: Since this is a bit obscure, I won’t keep you in suspense any longer. Here’s what I found:
As I said, I was stumped for a while. Using my architect’s ruler, I kept getting very slightly mixed messages. Logic dictated that given how close those results were, it made huge amount of sense that this would be the same roof on both.
But then I looked at the gap between the rear edge of the roof and the trunk opening. Aha! There’s no doubt that it was longer on the 2-door hardtop. Not much, maybe a couple of inches at most. Why GM though that small difference was worth tooling up a different roof for is a question whose answer has long been lost to the sands of time.
This can be confirmed by running a vertical line from the back edge of the roof. On the 2-door, it clearly ends a bit more forward on the wheel cover than on the 4-door.
But at least I can stop wondering.