Gday Tom, this what I carry for my MD17D.
Head Gaskets, ( the MD 17D has the three separate heads)
FW Circ Pump complete,
Fuel Lift Pump Complete,
Raw Water Pump impellers,
Spare Starter Motor,
Spare Alternator Regulator,
Copper washers assorted for injectors, fuel lines etc.
Lots of Lube Oil.
Gasket goop plus lots of other bits and bobs I don't consider essential.
I've had to make 'field expedited repairs' using all of them except the alternator belts.
What I probably should have but don't is a spare injector.