While we've got a 181 thread going here, let me ask what you guys know about head interchangeability on the Mercruiser. Talked to the machine shop that's doing my engine machine work today and they informed me that the head had a crack between the valve seats in one chamber. They also informed me that they have a fresh 153 Mercruiser head that was never picked up. The obvious question is will it work on the 181? Head bolt pattern is the same, I'm told. The 181 head has larger valves, but what about combustion chamber volume? Is it the same? I'm thinking it is, and the compression was brought back down on the 181 by dishing the piston rather than enlarging the chamber. The obvious difference is the port configuration, and the 181 head is probably a better breather, but I'm not concerned over a little power lose if the 153 head will work otherwise. Comments?
Bob
