coda2112

Hi, I had a custom set of headers made for my 1981 zz3 and now am trying to decide should I go with side pipes or dual under the car. Does anyone know if a compnay makes side pipes with cats installed inside? My problem is here in Calif. I will need to install cats dual or otherwise. Most likely if I go duals under ther car am thinking about having some exchange pipes fitted so I can just unbolt the cats, get it smoged then replace them with the exchange pipes (for the track of course). If I go side pipes am hoping the cats are built in. Any advice would be great. This is my third exhaust remode and it will be my last$$$ Also any comments on chambered duals? tnxs

joehalford01

the problem you run into here is that it's illegal to run dual cats on a single cat car. Lame for sure, but thats how it is. Either forget the cats and do what you want, then swap in your smog legal system for smoging, or build a nice system with a single cat. I can't decide which way to go myself either . I'm considering buying the 80-82 dual exhaust from mid america and fabbing up a bolt in catalytic convertor to use with it for smog (so i can switch back and forth easily). They sell a street legal system but they want a grip for it.

coda2112

Interesting, I didn't know that. I'm leaning more towards the full blows duals out the back with a cut out section on both so I can just bolt in a cat on each side for testing. I'm thinking the guys at the smog station don't know you can't run duals just as long as which ever exhaust they stick their little prob in there's a cat back in there to welcome it. I don't think am up to swapping out a full exhaust system every two years. Also, this F___ed up state is so hell bent on leather to rid all older cars that I get hit with a mandatory state inspection every two years. No smog test station, they want my *** to a state station. My car passes every time with flying colors and get this, I run a ZZ3 motor, pre 73 onlys, yeah right, a v-8 is a v-8. So for the smog police reading this, I will only run duals catless when am on the race track, never ever on the highways.

murraybs

for the most part, smog guys here in Sac will let it pass if it has one or more ACTIVATED cats, and all the smog equipment is on the engine.

If it's '88 or later it needs to have an EO number on the headers, but that's not a problem for any of us.

coda2112

Headers were custom made and look like factory but there far from that. So when you pop the hood visually they look like stock. That was the first part of my journey. There is NO ONE that sells SMOG legal headers for a 1981 corvette for a calif. registered car, NO ONE. I have researched this for about a year before spending $ on these. There are several companies that make smog legal headers for a 1981 vette, just not certified in calif. So, my last leg on this project is to go with true duals under the car and out the rear. Looks like they too will need to be custom made with drop in dual cats. I've seen some photos here on this site of project cars that look pretty good. 2 1/2 all the way back keeping it as straight as possible. Some cross member frame cutting is required but it's worth it. Any ideas and photos are greatly welcomed.