What Year Introduced Nylon Coated Timing Gears?

[Jon S]

I know steel gears were changed to nylon coated ones to reduce noise, but not sure what year this change took place.  Anyone know?

[TJ Hopland]

Cadillac for sure was doing it in the 472 when it was introduced in 68.   

Seems like everyone but Chev was doing it throughout the 70 and into the 80's. 

[Doc Hubler]

It certainly was in Oldsmobiles in 1966.  I suspect they started that in 1965 when they updated some of their big block engines (released the 425).  My 67 Toronado had that and I know the 66 models were the same.

[Gary McKinney]

My '66 Eldorado had them.  Still in perfect shape when replaced a few years ago at aprox 70,000 miles. 

[bcroe]

I've replaced them on nearly a dozen engines.  Never could hear any
difference in noise.  Bruce Roe

[Jon S]

I'm thinking 1965 was the changeover year. Anyone find them on earlier engines?

[TJ Hopland]

I wondered about the noise too, I never noticed a change.  Just seems like it had to be a pretty subtle difference, maybe if you didn't have the fan making extra noise you could hear a difference?

[Jason Edge]

They had the nylon coated teeth on the 1963 390 and 1964 429.