After all the good advice, the girding of loins and removal of engine; after all the grimy fingernails and stains on the driveway, the seemingly endless removal and inspection of various parts, the trips to the hardware store and parts store to repair/replace bad/missing parts, the cautious re-assembly, the waking up in the middle of the night realizing that I am friggin' /dreaming/ about the engine, and the various mechanical puzzles . . . after all that, the engine is back in the Wonderbus and running better than ever. The continual smell of oil vapors or exhaust vapors in the cabin are gone, heater air smells fresh, the clutch no longer makes that funny whining noise when the clutch pedal is down, the leaky main crank seal is replaced, the engine is much cleaner, runs cooler and instead of feeling like I was pushing the engine with the gas pedal to make the engine go, it now feels like the engine is pushing me.
My thanks and appreciation to all who helped me with advice and explanations and hints and tricks. I couldn't have done it without you.
Next up: passenger door still needs to be leaned into when opening from the inside to open, sliding door mechanism is getting stiffer and stiffer, speedo cable is making a squeaking sound, lighting for all the instruments except the aftermarket tach is too dim to read at night, passenger side headlamp points downward and the bezel resists all attempts to raise it up. Need to check and maintain wheel bearings and CV thingies and brakes.
I'll be asking more questions. You've not heard the last of me. Sooner or later I'll know enough to answer the rare question.