I have written off-list to David Sharpe about the questions he posed
in MMD 120410.  My public response deals with the two vent tubes that
he states are on his stack.  First, not one of us has seen all the
various combinations that Ampico conjured up over the years.  So
anything is possible.

It is my opinion that the two nipples he describes are not vents.
I have never seen permanent vents on any Ampico A stack.  Often, 7/32"
nipples are glued directly in the bottom deck of the finger flange
stack.  These nipples are the attach points for the pump amplifier.

The tubing from these nipples has a connecting straight nipple,
along with the expression tubes, that permits stack removal without
cutting tubing.  If in David's case, those straight nipples had been
disconnected, it would give the appearance that the part still
connected to the stack was a muffler tube.

There is no need to vent the Ampico A stack.  Muffler tubes are
normally present only on the crescendo slow valve top seat.
Conversely, the Ampico B has many muffler tubes.  I believe there
are 13 muffler tubes on the Ampico B.

A second possibility is that the stack lost motion pneumatics are
powered with the 7/32 nipples which are glued in the _top_ valve hole
in the deck board.  This makes it appear as if these nipples are
connected to the stack chamber, but they are not.  They are merely
connected to the lost motion pneumatics.  Like the amplifier tubes,
these tubes also have straight nipple disconnects near the top of the
stack.

Keep us posted.  We need to know if this is another variant.

Bob Taylor
Missouri