Here's "The man's"--author of
How to Rebuild Your Big Block Ford--response concerning side-oiler blocks. He doesn't answer all the questions, such as "what's that plug in the front for?", but it explains how marine blocks cause some confusion. Stayed tuned, but for now . . .
Code:
Tom, The picture with the block painted blue is a side-oiler casting-and appears to be a real side-oiler. The problem lies with the Marine Blocks. Many marine blocks were cast as top (center) oilers as well as side oilers; however they were drilled as center oilers only. The photo of the block you show is a side oiler only-the block the other person has could be cleared up with a photo from the rear of the block. All of the automotive blocks were cast as one or the other (always exceptions). The Marine blocks were cast with combo cores and drilled or machined as center oilers. Steve