unfortunately CARB are idiots.

what I mean by that is just because an item has a CARB EO (Executive Order) does not mean it is legal to use on our cars. they force manufacturers to pay for their products to have an EO and the EO is not attached to the engine, it is attached to the model of car. so Mustang aftermarket shorty headers may be legal in CA on a Mustang but most likely are not legal on a Panther. This being because the manufacturer of the product is most likely not willing to shell out the extra money to get an EO number on a vehicle they may or may not break even on for the cost of the EO.

Best way to go is custom catback. No headers. OR, get into a car club lol they always have smog hook up. I recrecently went to a big muscle car meet in santa cruz. There were about 300 cars, I think I was the only person who would have legally passed smog.

So I see that Magnaflow has direct replacement cat's chambered in 2.25, but does anyone know if they have the same, or similar bend cats in a 2.5 design? Or know of any other cats that will fit in the same spots, possibly cheaper than magnaflow?

check out 03redvicsport's setup- he ran all four 2.5" cats with his obx system.

https://www.crownvic.net/ubbthreads/ubbthreads.php?ubb=showflat&Number=2568951&page=40

not sure where he got em', but they're out there.

oops, thought I had it linked to the photos of his cat setup. it's in there somewhere.....

Dammit, the CARB EO cert is vehicle specific. Didn't know that. Why they should care as long as it passes at the pipe is beyond me.

JBA makes some shorty headers but looks like 2001 Crown Vic is specifically excluded as CARB legal. http://arb.ca.gov/msprog/aftermkt/devices/eo/D-216-23.pdf

03redvicsport moved his cats. Here in CA that's considered illegal even if you have all four present. They have to stay in the stock location to pass the visual.
magnaflow is the only company that makes ca legal high flow cats, but they are exspensive.
Im not sure if this will work but you could try to find oem cats from a shelby or a svt cobra. Somebody is always getting rid of them on cl. They flow well enough to support those high hp engines. The smog guy wouldn't know the difference.

they shouldn't. but then again it's not really about protecting the environment, it's about control.

So the only cost effective way to improve exhaust in CA is to swap out the mufflers? Been debating if I want to add flowmaster super 44s or magnaflows.

Talk to chris at adtr. His car casper is supercharged w/ longtubes. Maybe he can let you in on his smog secret.

Alright, time to resurrect this thread. The time has come to smog my Vic. Unfortunately the computers that run the test down in the I.E. (at least where I've been) can tell when a code reader has cleared the codes, and won't pass a vehicle if all of the diagnostic tests haven't completed. Problem is, once the tests are completed I get the 420 code. I was trying to put this off as long as possible, but the time has come. I'm still thinking 2.5 inch tubing, universal cats, and probably Flowmasters. Now for the questions. If I replace the dual cat setup with single universal cats, will it still pass the visual as long as they come with an EO sticker? The guy who did the smog check freaked out because he couldn't find the EO sicker for my K&N intake at first. Also, will deleting the second cat cause any issues with the cars computer because of the second o2 sensor that would normally be after the second cat? Thanks for any insight on this.

No, deleting the second cat will not cause any issues. Good luck man!

Do magnaflows. They have a straight through core. Only thing it'll really improve is sound quality though.

I'm also stuck in Kalifornia. After experimenting with just mufflers and tips on the stock system, I finally went for it and had a local shop bend me up a custom catback. If you take a good luck under your car, you'll see a flange after the cats where it necks down really small. I had them cut it off right there, install a 2.25" x-pipe, 2 really-short glasspacks(like 9") and 2.25" pipe all the way out back to 3.5" tips. When I first did this setup it was with 1-chamber flowmasters, which sounded like ass, so then I did the little glasspacks. It sounds pretty good, probably didn't make a bit of difference in power, but sure is fun. I have some mustang headers that I've toyed with installing but it'd be a hassle and I don't wanna have to pay a "special" smog guy for the privilege. Can't wait to move to a free state where the smog Nazis won't nail me for headers. I think the mod motors sound better with cats than without, but I would like the freedom to use high-flos with a larger diameter. 2.5" is too big for a stock or mildly-modded vic, which is why I went 2.25", because at most I'm going to throw on a plenum, throttle body and mzt. Watch a lot of videos before choosing mufflers, you'll regret it if you don't and change them a bunch of times like I did. Still kinda wanna go to spintechs.