Lots to consider
Where will it fit?
What has to be moved?
It’s going to weigh around 350-400 pounds. How will that affect the boat trim?
Where will the exhaust go?
Cooling water seacock and strainer placement.
Access for maintenance.
Fuel supply,, filter and return lines
Kw? Depends on what loads you have. Electric or propane stove? Air conditioning? After about an hour of running the loads drop off and start cycling. It’s generally bad to run a diesel long at low loads.
120 only or 120/240 VAC. Depends how your system is setup.
Starter battery location
1984 Monk 36 Hull #46
Currently in Cape May, NJ