73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: 73longbed on October 22, 2014, 07:37:37 pm
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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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Here is a pic of the number if that helps. Also, does the 5 to the left of GM mean anything? Sorry, I am a total noob.
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I have found that you can NEVER trust casting numbers to determine if an engine is a 4 bolt main. The only way to tell for sure is to drop the pan and count the bolts on main caps 2-3-4. Or main caps 1-2-3-4-5 if you have one of those bad boy engines. Lol.
Odds are the foundry left the "1" off of your casting number. Pretend like the 1 is there and carry on.