The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post

Dead Parrot · 08-23-2017, 05:38 AM

I think 'as shipped' dual cats are a rarity, even in the performance car area. Finding one for a truck shipped as an 'economy' setup is unlikely.

Doesn't mean you can't do one, just it is unlikely to find a factory type setup.

If you are trying for close to factory correct setup, avoid the old style pellet type of cat. Those do rob power. Go for the newer honeycomb style.

Check your truck GVWR of your truck. Might never needed cats. HD trucks of that era avoided many of the emissions requirements. My 75 only had PCV and THERMAC. No cats, pumps, canisters, egr, etc by being classed as HD emission. Restrictions tightened in later years.

08-23-2017, 05:38 AM	#3
Dead Parrot Registered User Join Date: Aug 2012 Location: Oklahoma City, OK Posts: 2,490	Re: Stock Exhaust and Cats I think 'as shipped' dual cats are a rarity, even in the performance car area. Finding one for a truck shipped as an 'economy' setup is unlikely. Doesn't mean you can't do one, just it is unlikely to find a factory type setup. If you are trying for close to factory correct setup, avoid the old style pellet type of cat. Those do rob power. Go for the newer honeycomb style. Check your truck GVWR of your truck. Might never needed cats. HD trucks of that era avoided many of the emissions requirements. My 75 only had PCV and THERMAC. No cats, pumps, canisters, egr, etc by being classed as HD emission. Restrictions tightened in later years.