with my headers on my 90 IROC i keep getting exhaust leak where the header meets the Y pipe. i once saw on horse power tv on spike that a company made a product that clamps the two pieces together so that it elliminates leaks. if anyone has any info that would be great.
there should never an exhaust leak with cast iron exhaust manifolds or headers, as long as you have the proper exhaust gaskets installed. if a proper gasket is being used, you might have cracks or holes somewhere in the system.