Hi all. I have stock exhaust on 87 gta 350. I have emissions problems and need a new cat. will a high flow cat help with emissions as much as a stock cat. I also believe the stock exhaust is 2 1/2 correct? Thanks in advance

 

High flow cat by itself won't help - but if your cat is not working properly, a replacement will clean it up enough to pass - assuming the car has no other problems.

Stock exhaust should be 3" on a L98. Do you have dual or single cats? I am a Magnaflow dealer and have sold several dozen replacement cats to 3rd gen owners.

 

yes..pretty sure cat is needed to pass smog. no other issues. its single cat. i believe its the original cat. so a high flow will lower numbers just as a stock one will?

 

Yes it should.