>The valves in my 83.5 waterboxer tend to be really loud on cold start-up.  

If this is happening overnight and you parked on level ground it's too
often.  If it's after a week or more of sitting or when parked quite tilted,
maybe OK.  It's the oil draining out allright, but doesn't matter if engine
is dripping unless the oil level has gotten too low anyhow.

CHeap fix is to get room for a quart of ATF and bung it in, then drive on it
for a week or so.  This will loosen/lift the gunge out.  Takes a couple of
hours to get things loosened up.  For a brandname fix buy a tin 8oz? of
Bardahl Hydraulic valve lifter additive and add. Works in about 10 minutes.
In either case when it starts quietly on a regular basis, or by weeks end,
dump the oil and filter and replace with fresh.  Lake Tahoe is ski area, how
cold??  I shift to 5W30 right now for the rest of the winter, it's  always
below freezing from now on, low teens overnight.  If you use 5W30 and the
clattering comes back go to 10W40.  This happens to me in the spring.  tim smith