We are going to replace the current intakes with new ones and add a third to act as a exhaust for this compartment in conjunction with the new engine blower system. . Overall, not a bad installation, except that the ventilation requirements of the engine are not satisfied by a long shot according to the engine manufacturer. In the picture below you can see a cross section of the boat where the ventilation is installed. The blue arrows indicate air flow. Cross section through the rear of the boat.
Green spaces are external.
An inquiry to Perkins revealed that a M60 in a temperate climate should have a duct diameter of at least 16 square inches. In a hot climate, the duct diameter recommendation grows to 32 square inches. Our ABS pipe weighs in at 3.5 square inches per pipe, for a total of 7 square inches of intake area. This 6 foot long pipe also goes through all sorts of convolutions to keep out water - further restricting air flow. Ideally, the engine would receive 247 CFM of air for combustion and ventilation.