Info on 165hp 250ci in line 6 cyl.

[gofastsandman]

The 292 is a long stroke engine and a 250 is more square which is what I would
want in a marine application.

Snort snort Delorean used a sohc head on the PMD sprint 250 motah which had a belt driven hot cam and a quadrajet carb.

The engine gained a reputation as a good performer at 250 hp, but the belts didn't last
and many failed at under 60 k miles.

As for your engine, I would take out the plugs and fill the cylinders with kerosene and ATF.
Let it soak for a week and turn it over to get the liguid out. Then spin it with an impact driver. Change the fluids and light her off. Then do a compression test. It may be in good shape.

Many engines sit for decades and can be brought back to good health.
If this is the case, I would then pop the heads off and check the extent of corrosion
in the jackets. The valve stem seals may also be dry rotted but that is a cheap fix.