One some of the later 427 blocks that were cast as side oilers but drilled as top oilers there is a machined area right where the side oiler "bump" is located on the driver's side of the block. What was the purpose of it? Was it only done on the marine 427 blocks or did the industrial 427 blocks have this as well. I searched the forum but it is still unclear to me which blocks have this and why.
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