Sierra Thermostat Housing MC861006A1 S/S 18-1989 by Sierra International $268.20 1 2 3 4 5 6 7 8 9 10+ Quantity Quantity Add to cart Sierra Thermostat Housing #18-1989 Stainless Steel. Mallory 9-42500, Mercurieser Stern Drive: 861006A 1, 8M0061381 Fits: mcm/mie gm V-8 (454 & 502 cid) engines