decode 440 blk

21046673 looks incorrect. last six digits should be the last of the vin, but should not start with 0. if it is a late built vehicle, judging from the cast date 4-28-71 it could be that last number did not show...46673X?

that would leave 210. 2 should be a letter like L meaning 440, 1 would be 1971 vehicle, 0 should be a letter like G, ie., St Louis plant, B Hamtramck plant.