We installed a set of the 220 ISB in Eastport hull #8- 2 years ago. They are actually an Italian based engine called Vinamatorie. Spellings wrong but phonetically sounded. They were actually the first set imported for Cummins into the US. They ran fine, plenty of power and torque, swinging 22x18 props (diameter x pitch). The only thing we didn't like was the idle vibration. If we bumped the idle to 900 it was smooth but to fast for docking etc. The other part is that in the mid-90's, Cummins fell behind in the marine market and people don't buy old technology. Cummins and Mercruiser have a pretty good package set up. One ugly point was the throttles had a mercruiser logo that couldn't be replaced without assin' up the whole assembly. Didn't have anything Cummins showing anywhere.
In a different boat, the Jarrett Bay 32, we did install a 425 Cummins on a jack-shaft sterndrive.