OK so a good friend of mine has a 50 AD that was put on an s-10 chassis. We are 95% sure it is a 1992 chassis with a 4.3 v6 and 700r4 trans. He purchased it as it is about 2 years ago and has really been enjoying it since.
He came by the shop the other day and wanted to know how hard it would be to put a heater in it (hasn't had one since he has had it). I had one out of a parts truck (AD) so we pulled it out and cleaned it all up and appears to be just what the Dr. ordered to get the chill off.
Now for the confusion.
The 4.3 only seams to have one port for a heater hose on the rear of the intake manifold (plugged right now) but none on the water pump as I am used to on sbc's.
Question is, where did the other heater hose go?
Any suggestions before I go out looking for somebody to let me look under the hood of their s-10 would be welcome.

Chuck