Update to my problem. After searching this site over and over came across a write-up on adjusting the TPS. My truck never did have real good power and this write-up perked my interest. The thing that brought me to checking this was in the write-up it says if your TPS is adjusted properly that when you put in the jumper in your diagnostic connector to check the timing your idle would drop down. Mine never changed. After I adjusted the TPS it would. Checked timing which was way off and put everything back together. Took the truck for a test drive and it runs great. Lots of power, no overheating, and the auto tranny even shifts better now. All becuase the TPS was out of adjustment. Might be something to look into Landozian. If you have any questions get with me and I will see if I can help. Been driving the truck for a couple of weeks in the near 100 degree temps outside and no hint of overheating at all.

 

Thanks for the update, I have a carbed unit, so no TPS, but I am starting to think it does have something to do with timing.

 

I had overhauled my cooling system--replaced it with a OEM water pump & tstat and off-brand radiator and hoses and my truck had almost the same symptoms as yours. After searching YT, I found out that I needed the tstat that allows constant coolant flow. I forget the part number but it's somewhere on the site. It's a tstat that has two openings on it--one big, one little. After replacing it, it worked fine. Actually, I have a couple pictures of the two different tstats.

 

I run a new water pump, new 3row radiator and 50/50 mixture antifreeze and guage never goes above half

22R (carb)