Braggs

Update:

I replaced the starter (since I have a new flex plate, didn't want to damage it with old starter gear) and the cranking has normalized quite a bit. Now it doesn't crank fast or slow, just a normal speed, even when the temperature rises after shutdown.

The heat soak is still present, however. When the engine is turned off for a few minutes, the temperature gauge climbs to nearly hot.

Someone suggested there was air trapped in the system? Any suggestions on how to remove the air from the system? I've ran the engine with the radiator cap off, maybe run it with the temperature sender out? If there's air trapped under the temperature sender, then removing it would release the air, ya?

GhostriderI

You said there could be air in the system. When you ran with the cap off did you have the heater on and set to max temp to flow water through the heater core? Also, Sender or gauge could be out of calibration (they never were accurate to start with) I have watched mine climb to the L on the gauge (in the summer with temps at or above 95) when I normally stayed at or below the R when driving. Also what mix of coolant are you running?
I have found, for me, if I am to much off the 50/50 mix the gauge will give these type reading on my truck regardless of the temp outside, she does not like to much water nor to much antifreeze/coolant in the mix. But that is just how my truck acts.

Johnboy429bbf

Last time I I had an air bubble in a cooling system in my pull truck. I parked it on the steepest hill started it and turned the heat on full blast. The bubble came out almost instantly.