[Bobnoxious]

Well, I can't tell you on all of them. 83 was 5.0 302 CI with single exhaust from the cat back. 84 5.0 302 ci with a dual cat back exhaust. I know those two are interchangeable and can be used on a 82 even, if you have the hole exhaust. I also seem to remember the 84 cam with factory headers. All GT's is what I am talking about.

 

[Bobnoxious]

Sorry it took so long to respond. We have been remodeling the house and haven't had much time on the internet. Yes, as far as I know through 85 they all had a single cat!