Posted for Bob <rbelshe@comcast.net>:

I'm using the small Stewart-Warner 8406R ol cooler on my 235 with
IO-320.  Air inlet is NACA duct on left side of lower cowl. Short piece
of scat tubing carries air into a fiberglass plenum which converts the
round tube to the shape of the cooler.  Oil cooler is mounted on
firewall with outlet air dumping into the space above the nose strut. Oil temps run 180-190 on warm days.  Seldom do I see it reach 200
degrees.

Bob Belshe http://home.comcast.net/~rbelshe/