Thanks, guys -

Here's the link from oldgmctrucks.com:
http://oldgmctrucks.infopop.cc/eve/forums/a/tpc/f/633004236/m/8311043482?r=2011065482#2011065482

This is going to be a working truck, hauling a lot of "stuff" for our horse farm, so I think I'll install it if it aids in more efficiently cooling the head.