Abstract: An end cone construction and related method for catalytic converters includes first and second inner and outer cone members, each with a small end, a large end and a continuous imperforate sidewall therebetween. The large ends of the first inner and outer cone members are connected with the small ends of the second inner and outer cone members respectively to create airtight seals, and define inner and outer cone assemblies which are positioned concentrically to define an insulating space therebetween. The small ends of the inner and outer cone assemblies are connected with an exhaust pipe, and the large ends of the inner and outer cone assemblies are connected with a catalytic converter can. A vacuum may be drawn in the insulating space to insulate the inner and outer cone assemblies.