There is a fellow here in the islands who has drilled out "side oiler" blocks, cast as such, but never "drilled" as such.
I heard those blocks were service blocks destined for agriculture,
oil rigs, industry and such. I wonder if that is similiar to the boat engine thing? Cast as side oilers, but never drilled as such.
This is one reason why it is SO difficult to "nail down" a "side oiler". I also understand the service blocks did NOT have any numbers or ID on them. What about boat blocks, for ID numbers?
There have been a number of "boat" counter rotation engines for sale, here and on e-bay, that were clearly "boat" motors AND were offered for sale as genuine "side oilers".