Hi Mitch,
Welcome to the forum, that is a a very straight D4 do you know why they removed the head?
As for parts the only place you can get liners in Aus is from Cat, they also have 90% of the gaskets. As for a head any late D4 7J and 2T will fit as they have the same engine.
After 2 engine rebuilds and one on the way I kind of know where to get all the stuff
I will send you a private message.
Regards