Posted for "Bob B." <rbelshe@comcast.net>:

 Airflow Performance makes a pump which I have been using since 1998 with my
 IO-320.  It cost under $300 then, I don't know what it would cost now. It
 has a flow through valve and has worked fine for me.
 
 http://www.airflowperformance.com/
 
 
 There is a picture of the installation on my web page, below.
 
 
 Bob Belshe
 Moraga, CA
 Lancair 235/320
 http://home.comcast.net/~rbelshe/