Reference Manual

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Chapter 9: Exhaust: Gas, Single-Outlet

All G-bodies (except some diesels and the high-output 307) use a single-outlet exhaust system. Its components include the headpipe, which connects the catalytic converter to the back of the passenger side exhaust manifold, the intermediate pipe, the muffler, and the tailpipe.

The G body single outlet exhaust system uses a pair of cast iron manifolds bolted to the heads. Tubular steel exhaust manifolds were used briefly on the roller lifter, 7A headed, 307 when it was first introduced. Exhaust gases from the driver side manifold are directed by an crossover pipe to the passenger side manifold. An exhaust pipe bolted to the passenger side manifold directs the exhaust gases to the catalytic converter mounted under the front passenger floorpan. The catalytic converter is of a dual-bed monolithic design. The first bed being a 3-way catalyst, reducing Carbon Monoxide (CO), Hydrocarbon (HC) and Nitrous Oxide (NOx) emissions, the second bed is a 2-way catalyst that futher reduces CO and HC emissions.

After the catalytic converter an intermediate pipe carries the exhaust gases under the propeller shaft over to the driver side where the intermediate pipe then travels up and over the rear axle to a muffler suspended laterally between the rear axle and the fuel tank. Exhaust gases enter the driver side of the muffler and exit from the passenger side of the muffler. A short tailpipe from the muffler carries the exhaust gases to behind the passenger side rear tire where the exhaust gases exit to the atmosphere.