Looked at a 69 SS with a 350/300hp. The casting was 3970010,is this a common block for an SS? All the other stampings are in place. The motor is April 69. thanks.

Yes, the 3970010 block replaced the 618 block and was phased into production in Mid to late April of 69. It's the only casting number for L48's and 302's for the remainder of the year. All 69 blocks used in Camaros are suppossed to be 4 bolt mains, although the blocks were produced in both 2 and 4 bolt configurations.