I want to put some AS&M headers on my 96 SS, it seems like i can get either a single or dual cat y pipe. Which one is better.

My stock setup is dual cats, and im not supposed to move the cats because i live in CA, but hopefully if i put a single cat y pipe on the smog man wont know that my car was a dual cat.

Thanks,
Greg

 

I think the single gets better horsepower #'s but you'd have to do some extra stuff to your exhaust because you have dual cats, I think.

 

A dual cat y-pipe will be better for flow since you'll have exhaust going through 2 cats in parallel vs. the y-pipe converging and forcing all the exhaust through 1 cat. I don't think it's worth the price though (Random Technology dual cat y-pipe $500+).

 

True, in theory.

Basically, 1 vs 2 cat y-pipe depends on several things- mostly whether or not you need to have the correct emissions equipment, or if you can pass with it slightly modified.
I bet you'd pass the sniffer with a single cat, but you'd fail a careful inspection. How careful are they?

I bought the mac header/y-pipe because I was concerned about passing emissions and inspection, but I had my car emissioned/inspected yesterday, and all they did was a cursory inspection and plug into the PCM port- does CA do that for OBD2 cars? If I wold have known it would be so easy, I would've went with longtubes and a single cat y pipe with sims...