I think he was referring to the heat riser that normally comes from the exhaust manifold, designed to help with those cold starts. The exhaust warms up the carb, and as soon as its hot the spring loaded dingus closes off the flow of heat.
When using headers, you have the option of hooking up a water heated plate under the carb, or ditching the system entirely. Search the archives here, I'm sure you'll find gobs of info - though not on that Pontiac engine.
-Boyo
