Ok well first of I want to make it clear that this car is never gonna be a monster racer. I am just about to order the 2.5 inch dynomax catback, but from searching it seems that everyone thinks that its too small. I just want to ask, is it too small if I am only going to do a few mods? If it is too small then I need to find a place with the 3" dynomax catback cause I have tried and I just cant find it.

 

I'd go with the 3" it won't be overkill. I would also suggest looking in a different section than the TBI specific for exhaust questions. This topic I'm sure has been beat to death, there are tons of exhaust systems for camaros I wouldn't limit yourself to dynomax.

 

I dont know what the hell to do I have been searching and stuff for over a month. I cant find a 3" system to save my life and I dont know how to order one from multiple different parts. I am about to say the hell with it and run 2.5 y-pipe, with the converter and catback and some junky small headers.

 

3 inches has proven to be "Just enough" for a 3.4L with some mods. There is no reason to go below 3 inches on a larger displacement engine. I even feel 3 inches is too small, but there are some guys who swear by it

Finding 3 inch catbacks is as hard as going to http://www.summitracing.com/ and typing in catback.

 

I dont think it would make much of a difference, the larger you go the more flow you will have, 3inch cat backs are whats preferred by the sports car enthusiast but honestly if its the price tag thats hindering you down I wouldn't do it.

I was gonna go with an American Thunder System not too long ago for about 335 bucks...now I am just gonna go with a simple exhaust cut out and maybe a cheapie dynomax catback system....I have no idea....try it out though you might score something

 

http://216.178.81.107/iwwidb.pvx?;multi_item_submit

I think this is what you're looking for, you also have a choice of 4 muffler types as well as ceramic or aluminized.

pypesexhaust.com

 

Oh, and for headers that include a y-pipe with 3" out try
Chevrolet Camaro 86-90 305-350 Hooker (shorty/Ypipe) 2055 1 5/8x3"
from jethot.com

You can order them cheaper from summit but it won't be coated. Coating is a must with headers, don't let anyone tell you differently. The only thing you'll be missing is a 3" cat, that one I can't help you with unless you get a universal to have welded in which is probably what you'll have to do.

 

Besides the Dynomax kit that you mentioned all TBI tailored cat-back kits are 3" with a 2.25" reducer that mates to the stock cat. The Dynomax kit is not a direct bolt on IIRC. If you are installing headers at the same time than I would select parts that are tailored for an '86 thru '92 TPI application. That was you will get a full 3" pipe without the reducer. You can then buy a 3" TPI or universal cat and mate it to your header set of choice.

If you just want to replace the cat-back than you have one of many choices to make.

Hooker
Mac
Flowmaster
Edlelbrock
Random tech
SLP

And many more make direct bolt on 3" cats with 2.25" reducer for TBi and LG4 cars.