HS2.8L Diesel

I have a Brazilian HS2.8L Diesel in my 1993 NAS D110

After experiencing white smoke, serious coolant loss and now coolant seepage around #1 fuel injector my mechanic has recommended pulling the head and replacing the head gasket. The head also might need repaired or replaced.

My question is where is the best place to find a new head if I need one?
I have heard the head gasket, water pump, timing belt and several other parts are interchangeable with the 300tdi but the head is not.

Does anyone have any experience with this motor?