I see a spin on oil filter which means to me no oil cooler at all. I suspect sky high oil temps causing bearings to be destroyed leading to pistons hitting the heads and broken rods exiting the side of the pan.

Don't think a good oil is going to fix poor engineering

exactly !!!! B/S setup and you were lucky for a while...as soon as you turned the key the pin was removed...need more oil, cooler, decent lines, etc...

Not sure on this setup but some people spin a filter on there during tear down to stop the oil from dripping on the floor. Before you crucify someone get all the FACTS not our own assumptions.

Point taken, Red, but from the looks of all those holes in the oil pan, I think putting a filter on there is not going to do much to keep oil from leaking out of that engine!

You can see the oil cooler and line in pic #2 on the first post.

Agree, brings us back to the bypass issue.

see what looks to be a cooler...I'm thinking was not hooked up...buy hey lets not jump to any conclusions...bottom line is this, it spun more than 1 rod bearing, no question, ran till destructed...reduced to door stop material...

I would like to see what the main brgs look like, if it was indeed an oiling issue the mains would show the lack of oil to some extent, and if they look decent then we can lean towards detonation. But lets not rule out rod bolt failure, leading to oil loss at the rods in question, then the snowball effect at 4900 RPM, then the inevitable. Forensic engine CSI can lead us down many paths, I know that if I was running at 4900 RPM with the design of my boat the wind over my ears, I would not hear a rod knocking till the engine quit(blew up) So this motor had to make some noise before it blew!

I have purchased a bunch of new and used parts from the OP and spoke with him on the phone a few times. He is not the type of guy that would run without an oil cooler. Now it does look like a stock merc cooler, was it cooling enough? Not sure if OP has oil temp gauge?