A coated metal substrate useful for carrying an exhaust emission treatment catalyst such as a three-way conversion catalyst for use with small engine platforms. The coated metal substrate comprises a metal such as a stainless steel, a carbon steel, a FeCr alloy, HASTELLOY.RTM. and the like. The coating on the metal substrate comprises an alumina silicate having alumina particles impregnated therein. The coating is applied using a liquid dispersion containing an aluminum silicate and the alumina particles are dispersed into the aluminum silicate coating while the coating is still wet. The coated metal substrate is then calcined. Thereafter, a washcoat containing an engine exhaust treatment catalyst may be applied to the surface of the coated metal substrate.