Confusing casting numbers

BBC

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Just bought a 454 mark IV block only. I think the casting number is 10068286, but the 5th # could be a 9. Then I read on Mortec numbers list that 10068286 is on the list, but not the 10069286. Then I find another Mortec list with 10069286, but not the 10068286. Confused??, are there 2 different blocks or just typographical error. Either way it says: 90-91 454 4 bolt short deck. Bob
 

63Half-ton461

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There is only one casting number in the 10xxxxxxx number seriues that ends in 286, if all the numbers u had were the last 3 it would be your motor.

Nice score BTW !
 

BBC

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Thanks for the reply- I think after squinting a lot getting the block out in sun light we determined it's a 9. You remarked Nice score BTW. So this is a good block? If you have some history on it I'm all ears. Thanks
 

63Half-ton461

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Well the 4 bolt main standard deck blocks came in corvettes and as crate motors , not sure they putem in many trucks if at all , the 4 bolt 454's are mainly a high performance casting so u dont findem willy nilly like ya do the 2 bolt main truck motors, yeah if i came across one (4b454) i would consider it a rare find. Of the 4 BB Chev's ive had only 1 was 4B and it was a tall deck 427 truck motor.
 

BBC

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For your info. the 286 blocks were cast in '90 and '91. They were used for Chevy RPO-LS6 and RPO-LS-7 Hi Performance short and long motors and the blocks were sold over the counter one per customer. They are just regular 4 bolt blocks but rare because only cast for 2 years. That was the end of the mark IV blocks, that's when the GEN 5 was born. Thanks I was hoping you had some more info. that I didn't know about.
 

63Half-ton461

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Find yourself a set a rectangle port heads and you will have the beginnings of an LS-7 ......
 
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