Well, on this 340 block, the smallest holes are in the middle and there are larger holes in both front and back. That is the case on both sides. So the casting or the drilling is not straight.
I really wonder if they were drilled from both ends. There are oil galley plugs on both ends of the block. It's hard to drill 30" through cast iron with out the drill leading off. I have read in Hot rodding Mopar small block books that you can drill the galleys out to the same size for more even oiling.
