Timing belts were an answer to Euro noise regulations. I don't know when these kicked in for real but they were being discussed for years. The debate was like the US debate over airbags. You could order them as early as 1976 but when did they become mandatory?

Fiat had one of the loudest engines on the market so they when all in with timing belts in the early 70's. It did cut the noise level and it was cheap. US cars from Ford that used Euro design engines, like the Pinto and Mustang Two, used timing belts.

Then the cheap thing caught the maker's eyes and everyone was using them. Hey, Government rules and all. Don't blame us!

So belts have gotten better but still.... I would rather trust a chain.

And the noise thing is still with us. It's why Porsche went to water cooling on the 911 and the VW van was water cooled from 1984 on. All those air cooling fins do put up quite a 'ring'.