My mom ruined our 1963 Valiant station wagon with slant six by driving with the oil light on. That was around 1970. I was only ~13 yrs old, but knew how to check the oil level, which was OK. The car made it about another mile before blue smoke poured out and the engine seized. She did get a nice AMC Matador station wagon out of the incident. Same thing happened to my 1969 Dart slant six in 1981. I stopped checked the oil was OK and continued the trip since the light went out. It came on 4 months later and wouldn't go off. I didn't know a lot about cars then and had few tools and gave up removing the oil pan, so parked it until I built a garage, then pulled the engine to rebuild at a shop (4 years later).
From what I now know, I suspect both problems were because the pickup screen at the bottom of the oil pan gunked up. If so, you can probably fix it without removing the oil pan. Drain the oil, pour 4 quarts of kerosene or diesel oil into the engine and let it sit for a week or as long as you can, then drain. You could even run the engine for a minute on the kerosene since stores used to sell "engine flush" which you put in place of the oil and run a few minutes. I think it was basically kerosene. Vegetable cooking oil might even be better since it dissolves stuff well. Diesel guys like to add a quart per fillup to clean the fuel system and bio-diesel does similar. The downside is veggie oil can attack rubber hoses (need Viton rubber), but should be OK if you just pour enough to cover the oil pickup (2 quarts?) and not where it will sit at the oil pan gasket. I wouldn't run the engine on it, but your call. Maybe 20 sec wouldn't hurt. Best to do this while the engine is still warm after a drive. Some people might use gasoline, but it evaporates fast, plus could catch on fire (don't smoke).
BTW, if you do decide to remove the oil pan, that is a pain. You must drop the steering linkage (need Pitmann arm puller) and loosen the engine mounts (need socket and breaker bar w/ extension) and jack the engine up ~2" to get room between the pan and K-member. You can use a little scissors tire jack from a newer car (cheap at junkyard, I've got several). Push it up by putting a board under the oil pan, then slide wood under the motor mounts to hold that position, then lower the jack so you can get the oil pan off. Since such a pain, buy the best oil pan gasket you can. I used a silicone one from Real Gaskets of TN on my 1964 slant.
