What years V8s used a nylon center camshaft geat?

They began using the nylon coated sprocket teeth in 1967.Continued up into the mid- '70's if I remember correctly...What year do you have?
Most lost the nylon by 100,000 miles so few remain.

I changed a number of those in the late 70s but could not place all the years.I was thinking about my 63 sport sedan.Ir has about 115000 miles on it[283 PG] runs good but those gears were in the back of my mind.Guess it will be good for a while.

Yes, thay will not have plastic but you will find the the chain may be stretched by now.If you do any long distance driving I would suggest replacing the chain.Will also improve the cars performance.
Years ago 100,000 always seemed like the life of the chain for most engines.