I just picked up a short block with the casting code 4010207. I have found the same number with a 1 in front of it on all the decoding sites and it shows as a common 1980-1985 350 4 bolt main. However, mine does not have a 1 in front of it, and it doesn't appear to have been worn off as the texture there is still rough like the rest of the block. A google search of this number leads to a long list of forum threads of people with the exact same question. Everyone tries to convince them that there must be a 1 there, but there isn't. I must have found 10 threads where people posted this exact same number, but none of them end with an answer. Has anyone ever seen this? Were a few cast with the 1's missing or something? Weirdest part is, in a couple of the threads the owner tore thier motor down and confirmed it was a 350, but it was a 2 bolt main. Any insight appreciated.
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