I see that you are from the UK.
Go on www.boatdiesel.com
and ask for Paul Foulston's help. He is a Cummins guru in the UK. He takes a very common sense approach and has done some "different" things than the norm from his stories.
I'm sure he can offer advice re the Cummins 220 in your application.
Plus he can offer some local help when the dirt starts to fly.