Hey guys, I have a 89 5.7 GTA with TPI. I removed the cat and put new exhaust from the Y-pipe back. I have been told that my car should have had two Cats on it. But it only had one, and it did not look like it was ever tampered with before I changed it. I also had an 88 5.7 GTA with TPI about 7 years ago that had only one cat. Why is this?
Thanks
Mike

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(Gran Turismo Americano) "The Ultimate Firebird"
Smokin 1989 GTA- Bone stock except for exhaust. (no catalytic-stainless pipe into Flowmaster 2 chamber).

 

IIRC, the 350's with dual cats had 3.something rear diff's in them, and the ones with a single cat had 2.77 rear gears. Check your RPO's.

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89 iroc-z 305 tbi
k&n filtercharger, open element air filter. nuffin' else

 

Thank Enkil, but what is IIRC, and how do I check my RPO's.
Thanks
Mike

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(Gran Turismo Americano) "The Ultimate Firebird"
Smokin 1989 GTA- Bone stock except for exhaust. (no catalytic-stainless pipe into Flowmaster 2 chamber).

 

IIRC stands for If I Remember Correctly. The RPO codes should be listed on a sticker mounted inside your center console.

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89 iroc-z 305 tbi
k&n filtercharger, open element air filter. nuffin' else