1970 Camaro Z/28 engine numbers - help?

[Dave Castine]

OKAY - got the story, talked to the previous owner who had the car for 20 years before the current owner of 10 years bought it (Uncle sold to nephew). The engine was rebuilt but he swears it's the original block. The numbers on the block are attached on the pics, the block is stamped as a correct for '70 on the back by the bell housing with 3970010. It also has the 12-bolt (70 only), 8k tach, LCA blocks on the bumpers, and being a NORWOOD car it has the Z28 called out on the cowl tag.