So I have an 87 iroc and I put headman shorty headers (HED-68470) on it, which is hooked up to the headman y pipe ( 17478). now I hadn't bought the exhaust yet, and I tossed the cat because it was rotted. Then I had to move the car so I just welded a piece of pipe to the rest of the stock exhaust. Today I just got in a new magnaflow cat back system (16829). Here lies my question. I live in mass, and I think I need a cat, but I don't have the stock one any more. What cat should I get to fit the hedman y pipe 1748 to the magnaflow 16829 system? And im not completely familiar with the purpose of the cat, since I don't have the stock manifolds anymore, and I eliminated the smog pump.

 

I think you are going to have to check locally. Here in PA it depends on where you live. Where I am at anything under 1991 is exempt but 30 miles to the west that goes all the way to 2000 and 30 miles to the south it is 1982 and everything after 82 not only has to have the Cat it needs to pass the sniffer per factory specs. Your best bet is just to ask the garage you are going to take it too or just take it for inspection and see what they fail.

If the system you bought was designed for a Cat I would make something up using the magnaflow Highflow Cat. That Cat does not need air injection but it may not pass inspection if you require a sniffer measurement. Heck if you need the sniffer the headers alone can be an issue. Does your car still have the factory TPI system? I have heard of some places not accepting after market Cats.

 

I think I just have to pass a safety inspection and not the emissions check. So I think they just have to see a cat on there.

 

Cat is not a safety item, it is a emission item so it sounds like you safety inspection has some emission requirement. I think you should ask the guy you are going to take it to for inspection.

Your only options are making a universal fit (normally requires welding) or finding a OEM or direct fit replacement. Some exhaust shop will fit a universal for less then a direct fit would cost. Most chain type exhaust shops will charge you more to fab up something then they would to install a direct fit. The direct fit Cat is going to hurt your exhaust flow but may give you a deeper/less raspy sound.

 

OP might be talking about a physical inspection but saying safety inspection. I've had to pass one of those on my 69 Camaro when in Cali. It was a 307 with a 2 bbl. I had to have the correct carb, factory air cleaner, PCV valve, and the heat tube from the exhaust manifold to the air snorkel.

No sniff test required just prove the parts are in place to get your tags renewed.

Truth is it was kind of silly. Most guys kept that stuff in a box and threw it on every two years for a day.