Obscure sources for GM catalytic converters?

This is a companion question to my P0420 post here: Understanding P0420 code on 2008 Pontiac G6 GT .

I am curious if anybody can recommend sources for GM catalytic converters beyond GM itself and the usual web search hits? My friend will likely need to replace the bank 1 cat on his 2008 Pontiac G6 GT convertible 3.9L engine, the problem being there are no longer GM cats to be had anywhere in the GM system, and the only aftermarket I can find is from Walker and designed for the CA, NY, CO, and ME markets, which would be overkill and pricier than what is necessary for us in PA. The annual PA state inspection mandates that the problem be addressed. I plan to start by replacing the two O2 sensors on that side, one at a time, but when it comes to the cat, I am looking for other options.

The garage that originally inspected the car mentioned he gets his cats (and similar items) from 1-800-EXHAUSTā€¦or something like that. Nothing like this appears on web searches, and this is the kind of obscure source Iā€™m looking for. I expect there are more. The garage that gave us a second opinion said he could get cats (he wanted to replace both), but it was unclear if these were GM or aftermarket. He didnā€™t elaborate on the make or the source.

Can anybody help?

Only one of the five cats on Rockauto is CARB compliant, $1,009, the other four are EPA compliant, $165-$358.

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Just curious for the experts here, is installing a used/ recycled cat allowed in some states? One from a wrecked & totaled car, car donated to a recycling program, etc.

As @texases says, just get the cheap one from rock. After market folks take over when the manufacturers discontinue parts. I bought one from rock for my Buick years ago and never had a problem. Under $200.

Since 2008, cars sold in PA must be CARB certified for emissions. (look it up online if you want) If the car is labeled CARB certified for 50 state sale, you MUST replace the catalytic convertor with a CARB certified replacementā€¦ I.e. the expensive cats, or you will fail the visual inspection. Look for the emission label underhood. If it is a 49 state car (non CARB) you can use the cheap cats.

It is illegal for any salvage yard to sell catalytic converters. The Environmental Protection Agency (EPA) considers it a violation of its policies for consumers to install a used converter from a salvage yard or sell it for reuse unless it has been properly tested and labeled.

According to the EPA, there are only three situations when you can install an aftermarket converter. They are:

  1. If the converter is missing from the vehicle when brought in for exhaust system repair
  2. If a State or local inspection program has determined the existing converter has been lead poisoned, damaged, or otherwise needs replacement.
  3. If the vehicle is more than 5 years old or has more than 50,000 miles (8 years/80,000 miles for 1995 or newer vehicles) and a legitimate need for replacement has been established and appropriately documented (e.g., a plugged converter or unrepairable exhaust leaks)

Any other converter replacement must be wit a ā€˜certifiedā€™ or new original equipment (OE) or equivalent converter.

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It looks like you are required to meet the CARB standards. MY2008 is the first year that CARB compliance was required in PA. You canā€™t use a catalytic converter that only meets US EPA requirements. The link below is from the PA state government and tells you what you need to know.

I wonder if that applies if the car wasnā€™t originally sold in PA? My truck was purchased out of state, but it doesnā€™t have a cat. My car waspurchased in-state, but it has never needed a replacment cat. So Iā€™m not sure what the rule is here in Calif . My guess is that an out-of-state car needing a replacement cat here in Calif only has to meet the original equipment specs where it was sold , not CARB specs.

If I had that problem Iā€™d still be inclined to replace the cat with a CARB-spec cat.

Kind of irrelevant since the car is in penn not cali. But whether to replace a $1000 cat on a $5000 car is an individual choice. Still I wonder if the parts are the same but just a longer warranty thus the added cost for replacements.

And we donā€™t know where the OPā€™s car was sold originally. I was just thinking out loud if the same applies in Calif or not. I have no idea what , if any, differences there are in CARB spec cats vs non-CARB cats. It seems odd that a car in PA would have to comply with Califā€™s rules, but I guess thatā€™s just the way the cookie crumbles.

14 states have adopted the CA emissions regs for cars and fall under ā€œCARB Compliantā€. More info here: