I Want to Purchase shorty headers and high flow cats, and My question about the cats, is will I be able to pass smog in California with the high flow cats?

Also I called a muffler shop and the guy told me that I have to buy 4 high flow cats to fit my truck, but Ive read other post where you can use 2 cats only is this true? and if so, will I be able to pass smog with to high flow cats and shorty headers in California.

 

I replaced my 4 stock cats with 2 high flows, and my emissions are lower now than stock, they burn cleaner.

 

So the muffler shop will be able to take the 4 cats off put only 2 on and pipe from the header to the cats.

Also I am gonna run a 3 inch cat back exhaust so should I buy 2.5 inch inlet/outlet size high flow cats or 3inch. because 3 inch would be good for the cat back, but is is the pipe size 3 inch from the headers to the cats or 2.5 inch

please help

 

its all 2.5" now, use 2.5" pipe and cats. I had a shop do mine for $40

 

Built54 - did it change the tone or volume of your exhaust significantly?

 

it made it deeper and more agressive. Well worth it.