How to Assemble the Front of a Small Block

I can only support seeing the bolt on 68 and later. Every 340 I ever had was equiped with the drilled bolt and that was alot of 340's over the years. I have seen motors that had cams put in where the bolt was not where it belonged. They probably did not even notice the hole.

I pulled a 70 340 apart and it did not have that drilled bolt. What size is it supposed to be so when I go to reassemble I can install it?