Mercruiser 4 Cylinder Exhaust Manifold | Barr Marine MC-1-52390 Cast iron combination intake & exhaust manifold fits Mercruiser 140 HP 181 CID 4 cylinder marine engines. Barr Mercruiser exhaust manifold Direct replacement Mercruiser 4 cylinder exhaust manifold Fits Mercruiser model 140 marine engines from 1968-1982 serial number 3332138 and up Designed for 2 bbl Rochester carburetor Includes gaskets and mounting hardware Heavy duty cast iron Painted black Replaces Barr MC1-52390 Replaces Mercruiser 52390A1 and 96705A1 Replaces Osco 6705