What's part of the package varies per year and per car model.

I think there are 1969 N97 cars. Or maybe called or coded differently. I remember 69 Chargers that got a dual snorkel air cleaner instead of an open element. not sure if turn down exhaust were part of that model and year package.


Also, there are emission packages that start in 1966.That was first year you see exhaust air pump's on Most Chevy's and Ford. Starting in 1966 you'll see green CAP control devices https://www.curbsideclassic.com/aut...irst-effective-exhaust-emission-control/ By 1970