I wanted to post this info to get some helpful feedback and perhaps new ideas, and just to put my mind at ease. My 1969 Z/28 seems to me anyway to be running hot even though the temp gauge shows well within the standards, reading barely over the first quarter of the gauge when driving and only going to the halfway point after shutting the engine off when I am guessing heat soak comes into play. Sometimes when I pull away from a stop after driving for a half hour the car bucks, backfires, and then stalls. I can't get it restarted for about 15 minutes until it cools down. When I open the hood it is like I can feel a blast of hot air. Previously the heat riser valve was stuck closed, but I had the flapper taken out. Wouldn't this mean that no more hot exhaust gases are being circulated up to the intake manifold anymore to warm the carb at start-up? When starting the car cold it does take longer to warm up now.
Is it correct that the sensor for the temp gauge is in the engine block? Is it possible the heads and intake manifold are getting hot for some reason even though the gauge reads fine? Could there be gunk blocking a coolant passage in the engine, fan clutch not working, smog pump or AIR system not working properly, etc.?
About 2 weeks ago I drove it only about 2 miles at no more than 35-40 mph. When I got to my driveway and turned the engine off and opened the hood I could see heat waves coming up from the passenger side exhaust manifold. It was a hot day, in the low to mid 90's. None of my other cars, or truck, put out anywhere near the heat that my '69 Z does. And yet the temp gauge still reads fine; could the temp gauge be inaccurate? My own thought is that I am boiling the fuel in the carburetor even with a heat shield, and that is why it wants to stall or kill and is so hard to restart until it cools down. Am I overreacting or misinterpreting something? Thanks guys for any and all help and ideas.