First, I want to thank everyone for their input on this matter. I really do appreciate it, plus all of these suggestions will serve as a guide for people in the future when they search the archives.

Muebweno: Excellent list that you provided. In my case, all but numbers 7, 8, & 9 are ruled out already. #8, inferior fuel I seriously doubt since I have purchased it from two different manufacturers at 4 different stations. #9, if the head gasket were bad, I would have other symptoms such as *very high* pressure in the cooling system which would then blow out through the pressure cap. Plus I am not loosing any coolant, and the system holds pressure in it overnight. #7 however, THIS I have not checked. The engine runs very well; I wonder if the timing can make this much of a difference on running temperatures. I mean, if it were significantly enough out of timing, would the engine not run poorly? A point to definitely ponder.

About you 1978 car - I saw on the CD that there are two different thermostat housing types, early & late. I know for a fact that the later ones are self-venting, but I don’t know about your ’78. You may want to try to bleed air out of the system. As far as your temps go, that doesn’t sound to bad actually. The only thing that I would check in your case is the viscous fan clutch – perhaps it isn’t engaging at higher temps like it is supposed to, therefore not drawing enough air while you sit still.

TxBill: I will look at my CD later tonight and get back to you.

240Joe: You are absolutely correct in the description of the flow path of the coolant. I have used the infrared thermometer on several points – on the head & on the block, on the area right around the temp sender to check for it & the gauge accuracy, and on the metal tube leading to the thermostat housing to check incoming water temp. And yes, ignition timing is a factor on gasoline engines.

Jeric: Yes. I believe it’s up somewhere in the beginning of this thread.

I REALLY wish that someone like Stevebfl would chime in on this thread.

THANKS EVERYONE!
RTH