I don't know how deep the oil is inside the pan, above the push rods. Do I drain the oil before changing push rod tube seals or unnecessary? Logic says yes, but the experts say - - -

NO

With a resounding NO, that's good enough for me! Thanks

Is the engine out of the car? On an engine stand perhaps?

Tall jackstands. I've pulled off all the heater parts except the heat exchangers, and it looks ok to do in the car.

Q? I plan to blow out each tube hole with compressed air before pulling it out, and then clean the area with a lint free rag before reinstalling the tube. Viton seals...just use motor oil on the new seal when installing?

Nope.

Just oil on the seals, yes. Clean up the bores in the heads and the case, yes. Make sure there are no ridges to cut the seals.

--DD

I'd recommend a bit of brakleen or carb cleaner on the outside (engine outside, the grimy part) of either end of the tubes before you pull them out, too.

And don't use chopsticks!
Andy