Then from 1969 - 1979 they made 350&39;s with this number and they were either 2 or 4 bolt main. Not sure about crankshaft, probably cast, I did not have the pan off, but owner says its a 2 bolt main. Engine code TJA. The 3970010 casting was only used during the latter half of 69 Camaro production (for 302 and 350 applications), but the block continued to be produced throughout the 1970&x27;s for 2-bolt and 4-bolt 350 applications. updated 16 days ago. You will see 4 bolt's holding on the main bearing caps (except front and rear). . The 207 blocks are a high nickel block and on the 010 blocks the blocks that jave K on the main caps tend to have a weaker main webbing then the 010020 blocks. 00-4.