Westerbeke 40 - Perkins 4-107 or 4-108 Block?

[Anonymous]

I keep hearing that the WB 40 is based on a Perkins block, either 4-107 or 4-108.  Brian at British Marine in Alameda, CA recently told me it is a 4-108.  Does anyone know the history of this and why WB used a Perkins block?

[SV THIRD DAY]

Rich, that's a 4-108 number. On those engines, the first 3 numbers are the displacement in cubic inches, the U means it was built in the UK and the rest is the serial number.