If that is the original chain the engine might be in exceptional shape for the milage. The chain is the best indicator of oil changes. It wears fast with dirty contaminated oil. The primary barometer in fact as nothing else in an engine wears as fast with neglect.

If the chain guide looks pretty good and no evidence of loose plastic. It should be good to go. I think at this point I will lay back in the shallows like an old alligator and see how things go for you. Keep posting as you go along. I feel there may be something to learn here.

What we do not know cannot hurt us is an old untrue expression. Had you taken the car in for a pump timing. Chances are the mechanic would have discounted your suspicion of the rapid recent chain elongation. Drip set the timing and further adjusted it a little to get rid of the smoke somewhat at best and that might have been it. The chances of running across a really good mechanic still interested in these older cars is not too good.

Sure enough somewhere far from home the chain might have parted. Had you not been checking the car yourself the sudden elongation would not have even been noticed. There are many other areas on these older cars that require some thought from time to time.

I really enjoy getting my hands dirty. Just not enough time usually. The local service places here are out of the question. I even have to service and source parts for our newer cars starting when the warranty ends. A lot of members talk about being leaned over their fenders. I just refuse to assume that position myself.