In 1997 it became a separate model designation for the sedan.
In 1953, the model designation became 475 and the grille bars were reduced to three.
The 3000 was produced in three marks and four model designations.
The various model designations are for different markets and case styles.
Eventually this was dropped in favor of using the manufacturer's model designations.
For 1963, model designations were changed once again with the 400 now called 440.
The engine and the model designation were altered again in the spring of 1955.
In 1961, the model designations were changed again, to 2600 and 2600L.
Some believed Boeing had skipped the 717 model designation when the 720, and then the 727 followed the 707.
All of the cars were updated in 1961 with a larger engine and new model designations.