With about a 6-7" cat installed. ;P I know from tearing it out with a drill, flex extension, and some type of polishing brush. I don't claim to be an expert at knowing the difference, but... this is direct from
http://www.gm.com/company/gmability/...ec_062006.html
"The engines also feature an exhaust manifold-mounted, three-way catalytic converter design. Constructed as part of the manifold, the close-coupled converter provides optimum light off (quickly reaches high temperature) to oxidize, primarily, hydrocarbon and carbon monoxide emissions. "