Any suggestions, help etc.?
>How'd you fix this?
>
Just let'em be!, they'll pump up again in a minute or so. DON'T rev the 
engine to help this out! Just let the 20-W-50 build up some heat and 
pressure to flow back into the lifters. My '78 also did this, especially 
parked on side hills. If it persists for more than 5 minutes without 
diminishing in fury I'd consider doing something. The Bentley manual covers 
bleeding (the tappets, not yours!).  Tilted parking also may get some oil 
into the cylinders, which is hard for the measly starter motor to churn up, 
especially in colder weather. I don't think I've left my  busses still for 
longer than 4-5 days at a time, you should run it every 2 weeks just to keep 
the batteries alive, and mice out of the heater boxes!   bye,    tim s.

PS.. has anyone else fought with pushrod tube replacement? Remember the old 
models needed to have the heads removed to do this, then the mid '70s could 
be slid out after rocker arm removal. So why furchrissake do I have to pull 
the heads on my waterboxer, don't the people who design these things fix 
them, or have a memory? My favorite vehicle now squats, pees, and oozes oil 
from its pores, charming, no?