I have a older mercruiser, I believe is a 120hp. First how do you tell the difference between the 120 and 140? I have a spare engine but no extra manifold. The block from my old boat has a external crack. But when I look inside the exhaust port of the manifold I can see a crack too. (I had water in the engine oil). The boat had came with a spare engine one was supposed to be a 120 and the other a 140. The spare head has larger valves then the head I took out of the boat. But the spare engine has cracked piston skirts so it will need bored and rebuilt. But I need to buy a manifold still. So there is a boat that is stripped with a engine in good running condition (we ran it) for sale for cheap. Only thing is it is a OMC leg and manifold. Engine has almost the same casting number and looks the same. The OMC manifold is brand new. I would like to just swap bell housings and drop this engine in. But will the OMC manifold work in the mercruiser boat set up? The only thing I really see different is the carbs sit 90 degrees from each other. Help!
