[Spridgets] Air pump ports

[John D. Caffrey]

   The idea of 7/16-20 came from measuring the mating air manifold. It is
   a  7/16-20  UNFstraight  thread,  it is not a tapered pipe thread. 1/8
   pipe  is  a  bit  smaller and the pitch is close so a 1/8-27 pipe plug
   screws in, that doesn't make it the thread size.

   John, Fogelsville PA

   Bud Osbourne wrote:

   Nope.  The  B  series head uses the same size as the A series. > Dunno
   where the idea of 7/16 x 20 came from.