I need two exhaust manifolds for my yamaha stern drive, the manufacturer says they are discontinued. can anyone recommend an aftermarket manufacturer, or know of someway to replace them?<br />boat- renken seamaster<br />engine-6 cyl 4.3L<br />year 1992<br /><br /> Yamaha exhaust manifold part # ysc 12191 10 oc<br />any suggestion is greatly appreciated