R Easley, YOu are correct about the 380 chain conversion hassle. I just did mine here at the house the last few months. For some reason M/B decided to tuck the intermediary gear drive for distibutor up under the left head. Anyway, I was able to determine I had an oil leak in rear flange, I was able to do a complete valve job and replace a few parts while I was at it on the injection system. Car does much better now and my air is quite cold with the 134a conversion, also.
For the cheap insurance of rolling a new chain in an overhead cam motor, I really don't understand the reluctance of some to do this. The M/B silicon/aluminum block is practically wear proof and requires only attention to those weaker items for that incredibly long lived engine life.
As far as the V8's go, they are more susceptible to the broken/jumped chain, however the poor little lady's car that I saw last week was of the small 4 cylinder variety. I do not know if the rail failed on that 190 or if the chain just gave out. In any case, she went too long before replacing it.
I suppose you could say that since I have background in owning/maintaining some expensive equipment (cessna, chris-craft cruiser, vettes and M/B), I don't have to be knocked down by overwhelming evidence before I choose to take pre-emptive measures.