Blocks that have more nickel have 010 or 020 under the timing cover, meaning 10% and 20% nickel.
That should be a 4 bolt main 350
it is a 1969-1979 motor it was used in cars, trucks, and vettes
The back of the block will have a series of letters and numbers cast into it. That is what determines the date.
1969
casting number 3970010 is a 350 block from 1969 - 1979 but in 1969 302 and 327 have the same casting # and im not to sure about the other #
1996
a 350 or 327 that is the question. A 350 or a 327
i called the Chevy dealership and they told me the year
you need the date code on the side of the block it will be a series of numbers and letters first its the month, then day, then year
Look at your oil filter housing and see if there is a 010 or 020 stamped there. This will tell you that the block was made with an extra 1 percent tin and 2 percent nickel content. That means it's very desirable for a performance block.
1969 to 1979 I've seen those blocks up to the mid-80's.
1968------327 & 1969-79 ----350