Review on Walker 81507 Universal Catalytic Converter by Robby Fingaw

It absolutely can be installed on California cars and meets the CA specification. I have installed it on my V6 Firebird (one of the CARB certified engine groups)) and according to the O2 sensor it cleans the exhaust very well. I was happy with the size of the catalytic converter (compared to other non-original cats). This unit was closer to the original dimensions, albeit not exact (16" vs 18"). Remember, this is a universal unit, meaning you'll only get one cat in the box with a warranty card. It has two 3" grommets on each end and you have to trim/clamp/weld a bit to install it. In my case I removed my old cat/y-pipe assembly and cut out the old cat. Then I used two adapters Welded 2.5" (my pipe size) to 3" and attached the cat to it. Then I reinstalled the Y assembly pipes. Worked great with no problems. Another thing I was happy with was that the mat that holds the backing in place covers the entire face of the brick.Some other cat aftermarket companies only cover about half of their substrate with the mat, so they need a special breaking-in process to extend it or they fall out. For this cat no hacking is required. I don't expect durability to be an issue as the engine runs well but if there are any changes I will amend this rating. For now, though, these are the only aftermarket cats. I will even install Walker CalCats on 48 state cars.