Saskatoon 9999
Ops jockey is correct and furthermore:
A300B4-622 is a A300-600 with PW4000 engines.
Also you say the original A300B4 "is much smaller" than a A300-600. For your Information it is exactly the same width of a Fuselage and Approximately 8 Ft longer than the B4-103/203 with approximately the same wing span. Basically the only difference bthe 2 A/C's are better Engines and more modern Avionics and a Few extra seats for the SLF(Self Loading Freight)