In 1972 what was the fastest four door production car in world?

There's no definitive answer to what the single fastest four-door production car in the world was in 1972. Top speed testing and comparisons weren't as standardized or widely publicized then as they are today. Different publications used different testing methods, and manufacturers' claimed figures weren't always independently verified.

Several contenders from 1972 might have been in the running, depending on the specific definition of "fastest" (top speed vs. 0-60 mph time) and which testing data you trust. Likely candidates included high-performance versions of cars like the BMW 2002, some Mercedes-Benz models, or possibly even a tuned version of a muscle car from the US. Without a single, universally accepted test at the time, it's impossible to say with certainty.