I just bought a set of Edelbrock shorty headers and am going to install them soon. I was wondering if I should replace the O2 sensors or cat at the same time? It seems like this would be the time to do it, just don't know if I need to. If yes, what brand O2 sensors and cat should I use? Thanks

 

It wouldnt hurt to put o2 sensors in the car I did when I put my headers on. As for the cat I just eliminated mine, But I dont have no emission test to pass in pa. What I would definitaly do while the manifolds are off is put plug wires and new plugs in it.It is alot easier to do when ther is no manifolds in the way.

 

thanks for the suggestion, anyone else?

 

I put in new O2s when I put in my headers. I got ACDelco O2s from my local auto parts store. A new cat might not be a bad idea if yours is original. They are only good for about 100k. If you do put a new cat on, I'd get a 3" in/out cat since most catbacks are 3" pipe, it would keep the cat from being a bottleneck.

 

If you have any doubts about the condition of your plugs and wires, replace them too. You'll never have an easier job replacing spark plugs without headers bolted to the heads.

 

replace those edelbrocks with something better.

 

Since o2's are so expensive I would just flame test them. Their is an article about how to do it on the net. Maybe someone here has it. I believe it is in the FAQ section on "The Turbo regal website". Sorry, no url. The info below was taken from the paper written and/or posted by Rick Kirchhof.

Testing O2 sensors on the workbench.
Use a high impedance DC voltmeter as above. Clamp the sensor in a vice, or use a plier or vice-grip to hold it. Clamp your negative voltmeter lead to the case, and the positive to the output wire. Use a propane torch set to high and the inner blue flame tip to heat the fluted or perforated area of the sensor. You should see a DC voltage of at least 0.6 within 20 seconds. If not, most likely cause is open circuit internally or lead fouling. If OK so far, remove from flame. You should see a drop to under 0.1 volt within 4 seconds. If not likely silicone fouled. If still OK, heat for two full minutes and watch for drops in voltage. Sometimes, the internal connections will open up under heat. This is the same a loose wire and is a failure. If the sensor is OK at this point, and will switch from high to low quickly as you move the flame, the sensor is good. Bear in mind that good or bad is relative, with port fuel injection needing faster information than carbureted systems.

ANY O2 sensor that will generate 0.9 volts or more when heated, show 0.1 volts or less within one second of flame removal, AND pass the two minute heat test is good regardless of age. When replacing a sensor, don't miss the opportunity to use the test above on the replacement. This will calibrate your evaluation skills and save you money in the future. There is almost always *no* benefit in replacing an oxygen sensor that will pass the test in the first line of this paragraph.

 

I would get a catback

 

They were around $30 each for me. Not so expensive.
And plugs and wires are a good idea too.

 

personally, i would sell the edelbrocks and get some long tubes. if yo NEED shorties, there are better brands out there than that. also get some good stage 8 locking header bolts and fel-pro gaskets. catback and a high flow/delted catalyitic converter wouldn't hurt either.

thomas

 

I have already bought plugs and MSD wires to install at the same time, I was just wondering if the O2s usually go bad or not. My car has 90,000 on it and I think I will probably do it just to be safe since it will be easiest to do at the same time as the headers.