I have been planning on getting the Hooker Catback for a while now and was reading in the Jegs catalog that it will bolt up to the stock converter. The current pipe is 2 1/2 inches and I have read that the Hooker is a true 3 inch I-pipe. My cat appears to be stock. I was going to get Hooker headers and a new cat so it would all be 3 inch but if it will bolt up to the stock cat I'll save my self some money and just get the catback.

 

exhaust will only flow as fast as the smallest point will allow it too. if i were you i would go ahead with the all 3" deal. if your just looking for better sound, then go with your idea, but for best performance results, going with 3" all the way will work best.

i don't run a converter, never have, but i have heard that the stock one sucks really bad.

 

Not true all of the time. The stock mufflers are horribly restrictive along with the crimped style stock pipes. Eliminating those few things on even on half of the exhaust is worth some noticable power gains. There is a balance between flow and scavaging.

The Hooker cat-back in question will have a reducer attached to it to mate to your stock cat. That is why you buy the one tailored to your year/engine car.

 

Geez! I wish this site would quit moving around, lol!

ZROC86, you can do just what you want to do. The TPI engine's stock cat has both a 3" inlet and a 3" outlet. So regardless of what size your current I-pipe is(which should actually be 2 3/4", not 2 1/2"), a 3" cat-back system will mate perfectly, providing it uses the same kind of connection, which you say it does.

 

85/86 were the years for the flange type connections on the cat so I would check that out. One of those years were different.