v-6 in early A-body
I had to have 5 timing chains put in my 92 Dak before 100,000 miles. The last one was installed at 115,000 and was the first time the dealer installed the chain tensioner. It was fine at 200,000 when I sold the truck.
I wouldn't hesitate to use the 3.9 at all, it would be a blast in a early A.