One thing I have to say about old cars and accidents:
A friend of mine had a 1967 mustang with a few upgrades to the body (minor things) to make it more stable and a bit stronger, and he T-Boned some new Japanese car that was participated in a street race, at about 70mph (average speed of both cars) and the steel mustang just kinda stuck in the plastic tuner like a knife into butter. Very little visual damage to the car compared to other accidents at this speed. As a side note I would like to add that I don't advice or suggest testing this as both people where hurt pretty bad, but the safety of each car is almost equal due to different construction.
Wow, I didn't know that Darts ever came with a 360. I was thinking about why you found it so difficult to time. If you use a timing light, it should be pretty standard if you watch the notch on the harmonic balancer and the marks on the timing chain cover. I'm guessing it should be timed at about 5° BTDC. It might be difficult to keep it in time, or it might go out of time, if the timing chain is loose and jumps, or if the distributor shaft is worn and is precessing around. Also, the oil pump drive shaft could be worn or its bushing could be worn, which could cause the distributor shaft to wander. The small-block Dodge is a great engine, and should last a long, long time. I agree, the Dart is a pretty good car even after nearly 30 years. I still saw them being used as the most popular taxi in Bolivia. They are simple and easy to keep running.
I own a 1979 Dodge dart and I have to say that they are very comfortable, solid, reliable and well made cars. Mine never has broken down on the road or give me any kind of trouble. My brother owns a 1976 Ford Maverick, and when I compare them, I can see that Chrysler cars were better made and designed than Fords or Chevys back in those times. Besides, the 225 slant six is a real beast of burden.