An acquaintance of mine "has" a set of true side oilers in his 38-foot Commander. Most of us have converted to the Pertronix ignition, or equivalent, because ignition points in a marine environment just don't seem to do the job very well. Our marine 427s don't turn any more than 4000 rpm (in a cruiser) so we don't need much in the way of exotics for ignition.
My theory about the marine side-oilers, is one of meeting the shipping order deadline.
I trust you'll agree, the true sideoiler is "a waste of good machinery unless it's on the race track". That's a loosely quoted statement from Carroll Shelby, when he decided to put the 428 in the 427 Cobra. He figured nobody would really know in a light car like that, because the 428 would still burn the tires off the rims for about a city block anyway, ha ha.
My theory is Ford was manufacturing side oilers, and they were jobbered out to local shops to do the gun boring. I understand a lot of blocks were wasted due to this process not being 100% reliable.
In any case, the theory suggests there was a stock of side-oiler cast blocks at Ford, but not drilled for the sideoiler function. These blocks were ideal for use in a Chris Craft cruiser, as they were cross bolted, big bore, great cast iron crank, and could use generic rods and low compression pistons along with "generic" 352/390 FE heads. Somewhere along the line, the shop foreman got in a pinch and "had to deliver". In order to make up the order to meet deadlines with Chris Craft, they tossed in what......I don't know......maybe 50 or 80 true sideoilers and shipped em to the CC engine plant at Galiopolis, Ohio where they were fitted with the marine cast iron and oil cooler pan, all the marine pumps and manifolds, thermostats, etc.
Internally the blocks didn't know the difference except for the cam and cam bearing, and of course, the internal oil passage and relief valve of the true sideoiler. Externally there was "almost" no difference. You and I could spot one a mile away, if we got a peek at the port side of the motor, but most owners didn't know the difference, nor did they care. CC didn't care either. There was no difference in power or operation, only a hassle if and when those exotic engines had to be serviced, because stock cam bearings will fit right into the sideoiler but won't work for very long.
Something like this must have happened. It makes no sense that Ford would unload valuable high performance blocks for boating use, when automotive enthusiasts would give an arm and a leg, and at least one testicle for one. Some people would give two, lol. As far as I know, all of the "other" internals are the same in a marine 427, and the only exception is the gun boring, cam bearings, and the oil journals on the cam itself.
We've run across a few of these in the boats. I don't think there are many out there. I'm fascinated by the history and sure would like to know for sure about "how" the sideoiler got into a boat. Carroll Shelby would probably roll his eyes about it. The sideoiler was so exotic, that even the oil journal is on the port side (driver side) so it centrifical force can help send oil to the bearings (NASCAR races turn left, oil is therefore thrown right, toward the bearings)....not sure if that's fact or fantasy.
At 4000 rpm max, I don't see "any advantage" of having a sideoiler in a boat. However, at the docks during cocktail hour, having a pair of these big dogs is most certainly an advantage. If you have em, you don't even need chrome valve covers!
regards, "P" (Paul )
1966 38-foot Commander Express
Origial 427 power