Did we scare off the OP?
Paul, I have completed a similar re-power in my 26' Nordic Tug. I downloaded all of the information from all of the diesels that were in consideration (Beta, Hyundai, Isuzu, Iveco, John Deere, Mitsubishi, Nanni, Sole, Universal, Vetus, Volkswagen, Volvo-Penta, Westerbeke, and Yanmar) and made an Excel spreadsheet to compare...
I listed critical boat dimensions:
- Top of engine bed stringers to underside of pilothouse hatch lid
- width of pilothouse door w/ frame removed
- width of pilothouse door
- min height of pilothouse door
- min width of passageway
- min width of companionway doors
- Distance between engine bed stringers
- width of the stringers
- distance from the top of the stringers to hull
- propeller shaft flange to forward bulkhead
I compared ancillary equipage location:
- alternator side
- starter side
- transmission control side
- fuel inlet side
- raw water pump maintenance clearance
- fuel filter clearance
- oil filter clearance
I compared engine dimensions:
- front of engine to gearbox output flange (OA length)
- Front of engine to forward mount
- Front of engine to CL of rear mount
- Engine mount to engine mount
- Rear Engine Mount to Output flange
- OA width
- Mount to mount (CL) width
- OA height
- Crank to top
- Crank to bottom
- Crank to output flange
Now you know what will fit.
Of course price and delivery were compared along with critical spare costs.
I created hp and torque curves and plotted them on the same axis spacing (tricky engine manufactures change plot to make them look flatter) like the graph below.
Now you can play around with prop calculators, specific fuel burns and the like to optimize you cruising speed. Make sure you know your prop clearances.