If it were me, I'd pour oil
on the valve train rocker arms. even if it was just dump a quart or two as fast as you can in the filler hole.
You can pre-oil by removing the sending unit and even using a cheap
garden pump up sprayer or anyway you can gt at least 10 PSI or more of oil
in that hole. If you have de-compression levers pull them and motor
her over a good while, idea being to get oil everywhere before the load of compression is put on the bearings.
If I didn't have de-compression levers and didn't pre-oil, I'd pull the injectors to relieve compression and turn her over. If you pull the injectors, a tablespoon of oil in each cylinder wouldn't hurt, but it will blow some out of the injector holes so have a rag laying on top to catch what is blown out, you'll need the rag to catch the Diesel
from the injectors anyway, each shot is only a tiny amount of course, but high pressure.
Of course you know have a new impeller. After starting, I'd run her at high idle, say 1,000 RPM
until she warms up and change oil.
Then I wouldn't run her too much until I could get her under a load and actually run her pretty hard as there may have been a think layer of rust form on one or more cylinders and you want to ensure the rings stay seated / worn in.
I'd have the intake open and a piece of wood handy too, that way since your prepared she won't run-away on you.
While your doing all this spinning things over to distribute oil, maybe have the seacock closed.
I suppose or at least a new filter, watch for clogged fuel
lines too, and a dirt dobber nest in the fuel tank