Posted for "Ed Anderson" <eanderson@carolina.rr.com>:

Rusty, FWIW

     You can get an AN16 male fitting that will bolt to the thermostate holes
(if you have an engine with the two bolts rather than the 3 bolts). The are
the AN16 fittings designed for a Chevy engine. Here is the URL of one
similar to mine (mine does not swivel)
http://www.csiperformance.com/cooling2.html
That is what I use with a gasket between the AN16 fitting and the the
thermostat housing.

   Also, the 1986 water pump inlet tube is just the right inside diameter
that you can use an AN16 or JCS tap and cut threads inside the tube.  Then
you can screw a AN16/AN16 adapter into the water pump inlet tube (with a
soft aluminum washer around the AN16 fitting.  That way you end up with two
AN16 fittings on each end of your pump.  You might be able to rent such a
tap, however they tend to use a JCS designation instead of AN.  I borrowed
one from old man Lou Ross and don't have one myslef which is why I don't
change my water pump housing to a later model {:>)

Ed Anderson