My truck still runs great, but it is putting a lot of oil into the catch can.
at 460,000 hard miles, might be time for a re-ring, but when I pulled the hear at around 300K there was still good crosshatch, so could it be the rings are just gunked up?
Has anyone tried pulling the injectors and filling the cylinders with acetone/atf to cleanup sticky rings?
I guess another option would be for me to finally install the water injection system which cleans combustion chambers, maybe the rings.

 

Rings lose their spring that holds them to the cylinder wall with time and heat. Rings are also designed to wear faster than the cylinder walls. Cheaper to replace rings than rebore and hone cylinders. Considering your mileage, I'd say wear is your culprit.

 

Also worn vacuum pumps have been known to pump excess air into the crank case giving the appearance of excess blowby.

 

Or even ripped / open ended vacuum hoses will make excessive blow by out the engine.

 

Have you done a bleed down, or compression test yet?