I've written a bit about the Tatra 603 elsewhere, but in summary, the Tatra 603 was introduced in 1956, after a design process that took 3 years, and borrowed a bit from earlier Tatra designs. It had a number of typically "American" features, including a HEMI V-8 engine, dual exhausts, and tailfins, while also having some distinctive Czech features such as a rear/rear layout and an air-cooled engine. The engine was also, in spite of being a HEMI, only 2.5L displacement, in contrast with the Mopar "Firepower" HEMI of the time, which came out to roughly 5.8L.

The purpose of the Tatra 603 in the Czech "market," if that's the word, was to serve as a domestically-produced alternative to Soviet-built luxury cars issued to the Communist Party. The only users of the Tatra 603 who were not in the Communist Party elite were the Statna bezpecnost (StB), who were the Czech Communist secret police. Otherwise, the vast majority of Czechs (who qualified to have a car) were issued with whatever the current model of Skoda was.

The Tatra 603 received two facelifts, in 1962 and 1968 although both had only a minor effect on its appearance. The more significant would have been the 1962 facelift, in which the original, unusual, three headlights were replaced with a more-conventional four. At least a few 1956-61 603's I've seen, though, have had five headlights, but I don't know if this was an original factory option. This is an example of the five-headlight configuration:

upload.wikimedia.org/wikipedia/commons/thumb/0/01/Tatra_603.jpg/1024px-Tatra_603.jpg

Judging from the headlight design on the 603 in my photo, this appears to be a 1968-75 model, although I don't know the precise year.