ASK RAY

CLEARING THE AIR ABOUT CATALYTIC CONVERTERS

Q: We were trying to decide if we should use catalytic converters on a vintage Chevy truck project that will receive a circa-2007 Chevy LS (Gen III) 6.0-liter truck engine. It will be controlled by a programable system, and it will wind up with a cam that isn’t too radical — it has a 113-degree lobe seperation angle.

The truck we’re building is from the pre-emission era, so it doesn’t require catalytic converters, but someone else expressed that, “If you don’t want to stink of gasoline fumes all the time, use the cats.” I’ve thought the smell from the exhaust has more to do with the tuning than whether or not cats are used, but I’ve never actually tested that.

Would it be feasible to do a proper tune on a vehicle like this without cats, and have the exhaust not stink like an old car? Shouldn’t efficient combustion alleviate the traditional heavy, lingering exhaust fumes? Or does the conversion done by the catalytic converters really take