A little history, the boat sat in my dad's back yard for 25+ years.
It popped a freeze plug one season, and sat parked after that.
15 or so years ago the freeze plug got replaced, then the steering and forward/reverse cables were in need of replacement.

He offered the boat to me on vacation one year and said I could tow it home to SoCal (from MN).
A couple years ago I talked my dad into getting it running again.
We replaced the trailer tires/bearings etc. and towed it to their lake home in northern MN.
Sadly my dad passed away before we could get it running. 

I'm back in MN on vacation, and we decided to get it running again.
I worked on it a little, but tools/time were limited.
Replaced the starter, yanked all the crusty/corroded wiring, installed a loaner carb, and rigged up a temporary set-up to try and crank/start it up.

I primed the oil pump, and cranked it with the result of no spark.
Replaced the coil, checked again, no spark.
Replaced the points, and nice fat blue spark.
Fed the carb a little fuel, and it fired right up, but promptly dumped the oil from the filter.
Checked the filter and it was loose, so tightened it, refilled the oil, with the same result it dumped the oil again.

Removed the filter, gasket was blown, replaced with another new filter.
Refilled the oil, and tried again with the same result.

Not knowing anything about Chevy engines, I'm guessing here?
Probably the relief valve in the oil pump is stuck?
Huge bummer, as the engine has to get pulled to fix this?

I removed all the wiring it was in VERY poor shape.

Doubt a 41yr old electric pressure gauge would have been much use?

Plan is to rewire w/ new gauges. Wanted to see if it would run.
It seems to run well enough to proceed.
Engine fairly low hours/usage, just sat for loooong time.

My thinking is the relief valve in the pump is stuck and the filter can't take the pressure.
But, like I asked don't have any Chevy knowledge.

Oil and filter was clean no weird stuff.
Engine was primed via drill fixture.
1st new filter was AC pf35?
2nd new filter was a Fram don't remember the #.
(it was Sun. and only local fleet store was open)
walmart open as well, but they only stock fram as well.
small town and selection is pretty limited.

Both filters the seal blew and a LOT of oil dumped.
Refilled it w/ new oil both times and it came out clean.

Only ran the engine for a few seconds each time.

Interesting you mention using a filter w/ built in bypass.
Have a part#?
I have no info on this engine other than it's a 454 built for use in this boat.

I removed all the wiring it was in VERY bad shape. Frayed/cracked/corroded.

The oil sender wiring was shot.
Wasn't planning on working on it or I would have been more prepared.

The oil pressure is likely very high since it blew 2 filter gaskets out.

The only wiring right now is a coil wire w/ switch, and a starter solenoid pigtail for use w/ remote start switch.
When running there was no lifter/valetrain noise so oil was up there.

The oil pressure is likely very high since it blew 2 filter gaskets out.

I understand that, but without a gauge you really don't know how high it is, not the best way to run any engine.