I Have a 89 Camaro it is a 305 TBI Automatic. Im in the mittle (closer to the end now ) of changing out entire floor pans, man were they bad! This is my first project car so go easy on me... No upgrades as of now want to do a little work to the top end later on. Basicaly I am going to beef it up some. But would like to switch over to true dual exaust, first. Yea i have read, on the fourm, about how much of a (fill in the blank) it can be. But, thats the way i would really like to go. So knowing that it is going to be a semi-beefed up 305. What size pipe should I run? Ive read through and seen Wille's true dual exaust, and know that it is a Z28, but he ran 2 1/2 is that what I should run as well?

Also, we will call this question two, I never really tryed to do a search on Cats but was on fourm seaching a lot yesterday, and never got finished so i'll just ask. Want to know what kind of cat's i should be getting for this application. I see most guys not talking about them on the fourm when they tell what they have done to their exhaust but i live in IL and we have emissions (and salt). Any links to helpful sites/pics would be appreciated.

For now its back to floor pans.

Thanks,
Chrome On Rust

not to put you down or anything, but with a semi beefed up 305 a good set of headers and y pipe along with a 3 inch single catback will flow plenty enough for your mods. But if you want to go dual, 2.5 inch will flow plenty enough

the only problem with duals is that there is almost no space under the car. a few days ago a member posted his way of handling it - he used some flex pipes.
and it looked pretty good.
just make sure you read a lot to make sure you know what you want.
most people use the passenger side for the pipes because that is where gm put the heat shield.
have a good time, you will love it.

2.25" Dynomax, bolt on kit.....Size should be good for a 305.

https://www.thirdgen.org/forums/exha...ms-solved.html

All aftermarket Cat's are hi-flo, so really doesn't matter on a Cat - they are all the same for the most part.

Anyone else think this would be the way to go?
I saw that it was 2.25 tubing and not mandrel bent. Is that going to be an issue at all, or would 2.5 mandrel bent add a noticeable diffrence?

Thanks for the help so far all.

If it was me unless less your planing on building 400 plus hp motor in the future I would put a set of good shortys and a single 3in exhaust! I have hooker 2055 and a flowmaster force2 3in and love it.. not to loud! But im in the process of putting hooker ceramic coated long tubes and 2.5 duals with a x-pipe!

I agree with this guy....shorty's, and 3 inch unless you plan a bigger build later.

I have stock I-pipe (2.25 maybe?) on my 350, and I get plenty of flow - my headers reduce to match the stock cat, and I'm running an Aerochamber muffler.

So there is going to be no gains beteen the true dual 2.25 over the one three inch? I mean i really would like to have duals but if it is only going to hinder my preformance then i would rather have the 3in.
Thanks

with your motor now a single 3in is more than plenty! you problely wouldnt gain any power with duals ..you could go duals if you want but its going to be a hassel and loose ground cleance! I think you would be more happy with a good 3in set up!

3" single.

For what it's worth, after much reseach that's what I'm going with
on a pretty highly mod'd 350; Hooker shorties, Doug's (cheaper)
Y-pipe, short high-flow cat, and Dynomax cat-back muffler system,
all 3" components. Only caveat is that the y-pipe has a 2.5' collector
outlet. But I think (actually hoping at this point) that I can trim off
some of the outlet, opening it up to 3", and then weld on a 3" section.
At the risk of incurring environmentalist wrath, I won't talk about how
I intend to fab some ball-socket connectors into the system. Then I can
run a straight pipe 364 days a year, and cat section on inspection day.