[Christ]

It's not the starter that's causing the problem... that's actually new and spins the engine plenty fast under normal conditions - It's the engine itself, or the injectors, more appropriately.

They bleed off pressure while it's sitting, introducing air into the fuel lines, which causes a no-start issue on the International 6.9/7.3 family of engines. Spinning the engine faster always gets it to start [like using a boost charge from another car to increase the system voltage], or spraying ether in it.

Since I now have to drive the truck full time again, I'm gonna try to pull the injectors from my old 7.3 that ran well and see if those clear up the problem til I can find another motor to toss in the old beast [this one needs more work than just injectors].