How do you know it was a 440 car? I thought that the 440 was only available on the R/T and the 440+6 on the Super Bee?
What is the VIN?
Are you sure its not the 440 trim level that was available? I would imagine that going from a 440 to a /6 is alot more work considering you would need a different k member, transmission, rear end, and not to mention the radiator outlets are different as well as the throttle cable, wiring etc.
Just curious because I know alot of plain jane C bodies came with 440's, but i don't remember plain b bodies with them too. The largest i've heard is the 383 4 bbl versions.