Check the tuning first. Excessively rich exhaust will damage the cats.

I have the same issue on my 442. exhaust routed out the back. But if the windows are open, I create o low pressure zone inside the cab apparently and it sucks up a good portion of the exhaust through the trunk I guess. I've tried taping all the gaps, but I still reeeek after a drive which my wife hates.

Walker has a lot of great info on Cats, especially the break-in period and how its so critical. I am planning on getting two walkers(OEM) high cell count, yeah I know, not high flow, but I'd rather trade some power for clean exhaust. I'd be real curious to know if the Thunderbolts clean up the smell to your satisfaction.

As far as the tune, if your tuning with EFILive I can suggest some values for injector EOIT I found worked for my 6.0L LQ9, depending on your setup it may help.

The thunderbolt cats are 300 cell hoping to eliminate or minimize exhaust smell. The reason why I went with Thunderbolts is that they are compact cats. I have not installed them yet. Maybe sometime in March I am going to install them and let you know how it goes.

I also need to check the tuning.

What's this world coming to, people can't even enjoy getting smelly in an old hot rod anymore. :D Pass the grey poupon and hail my Mercedes Benz my servant.

Did you get those cats on yet? Curious if it helped, hurt, how much quieter is the car, etc.

I don't have an LS (I'm running a EFI Gen I sbc) but I have high flow cats from Walker.

I too got tired of the exhaust smell a long time ago. Didn't feel any impact to performance. But it did quiet the car down significantly.

I have the cats but have gotten the chance to get them installed yet.

Exhaust smell gets annoying sometimes. I am going to receive my new my mufflers this week. I have ordered race venom mufflers, and I am planning to modify from H pipe to X pipe as well

I was just going to look into this. My car has been tuned and after some recent changes, retuned. I still get the smell and would like it gone. Room wise-I'm quite limited underneath. Just interested to hear how it went.

Bought the cheap Magnaflow ceramic cats and installed them in my car.

Much quieter and better sounding with the blackheart mufflers that were terrible on their own.

I don't smell like exhaust after driving the car anymore. I call it a win.