I want to see what year my block is,I have a sbc,how do you know what year it is?

phone a chevy dealership parts counter with the serial number off the block......the stamped serial number....... and........the casting number which is cast in the block on the transmission mounting flange to the left of the distributor.......eg. my blocks casting number is 3970010 which is known as a 010 block.....pre 87 350 4 bolt main block
The right small block chevy book will tell you too
Are your valve covers of the the centre bolt hold down variety??....if so.....its a post 87 block.......if perimeter hold downs pre 87.

it does have the center bolt valve covers,I am prob buying a new shortblock from a friend and have a balancing question in a different post.