>Duuuhhh, it sure sounds like the main bearings to me.  That is EXACTLY  the
>sound that they make (and so described by Muir).

I really don't think it's mains. I've never had mains go bad (has anybody
on this list ever driven the mains out of an engine?) but Muir says you
feel it more than hear it. This sucker is loud. I can feel *something*, but
it's pretty subtle, and whatever it is could be anything in the driveline
and may just be coincidental with the noise. This is sort of a beater,
there are enough vibrations going on to attribute anything to anything
else, believe me. ;)

Also, I mentioned previously that engine speed makes no difference. I can
be going 45 in third, then shift to fourth, a difference in RPM of [I'd
tell you if I had a tach, feels like ~900-1000] and it makes no difference
in the noise whatsoever.

And I had a good flail at the pulley; there's no discernible end-play at all.

>A better possibility (and cheaper) is air leak into the passenger
>compartment.

This is certainly possible, and I'm holding it open. There are air leaks
galore--but no new ones that coincide with the sudden appearance of the
noise.

>Another possiblity ( and even more scary) is the ring and pinion gears of
>the trans.

This scares me the most. Hoover says it's easy at *his* house, but most of
us can't fabricate an entire bus with nothing but a loincloth and a pile of
iron ore. I have a spare trans but using it would make the possibility of
putting the '71 back on the road this year very remote.

Thanks for all the help, everybody.

--Ken
  '71 Bus, '68 Westy