I want to complete my 3" exhaust with headers and a new cat. I am going to get the SLP's but I am not sure what cat to get. I already have the 3" hooker catback but the reducer at the cat will have to be cut off to accomodate the bigger cat. I was looking at the Dynomax 3" cats (from Jegs) but I am not sure which ones work with my car. I need a three-way with air inlet...right? What is the diff between them and which one will work on a 305 TBI?

 

i wondering the same thing today and after callin aroudn i foudn our that on the 305 tbi with air we need the 3-way.

 

I thought I needed a three-way but I wnated to make sure. Is this a pretty good cat or is catco a better one. I figured since I am keeping the 305 it wouldn't really matter

 

I'm in the same boat with you. I've got the Hooker catback, but it's got the reducer on it. I'm trying to decide what headers and cat to get. I want a 3 inch system as well.

I'd like to get the Edelbrock TES headers with 3 inch y-pipe, but I'm not completely sure yet. Which SLP's are you getting? If I get the TES's it's going to cost me $315 + $180 for jet-hot coating on just the headers plus shipping. I'm not quite sure what to do yet though.

 

i have the tes headers and i love them but i wish they were coated. summit has free shipping

 

I was going to get the expensive SLp headers. The 1.625" coated ones with AIR. It is hard to justify 608 bucks for headers. I was going to get the hooker shorties (2055's) but I hear the ball flange is to small (1.9" i think). I was going to get a three inch cat from dynomax. It is 18" long so I should have room to cut the reducer off of the hooker cat back and have the new cat still reach. I might get the enlarged tbi unit from turbo city with the AFPR so I don't run lean once I get the three inch set up. I will keep my results posted. I might wait for another group purchase. If not by the time I get the headers, cat, install kit, and labor I am at 1000 bucks.

 

Stock actually is a 2-way with AIR. You dont actually need AIR injection if you run a 3-way cat conv. The LT1 Camaros are an example of the 3 way cat with no AIR.

 

I thought LT1's were supposed to have an electric air pump.

I know my cavalier has a 3-way converter without air, but I figure that's because it's such a small engine.

 

So what do I need. I need a three inch cat in/out but what do I get. Three way? two way? AIR no AIR. I want the car to be legal and I am going to buy headers will all of the emissions stuff onit. I just need a cat to match all of it.

 

This may help some. I'm doing about the thing same as you, and I'm getting the Catco 3 inch in/out 3 way with air. I think this one is the one we need. I don't think ours came with 2 way converters, I think we had 3 way's stock.

 

You are correct!