overheating issues - 79 k10

[Stepside Man]

I am a former radiator mechanic.

Did you use silicone anywhere in the building process? That can travel through an engine and end up in weird spots. Seen it many times.

Try running the truck with the thermostat complete out of it. You may have a stuck shut thermostat.

Air binding is usually not a problem with these trucks. As long as you have original style radiator. The high point in the system is the radiator.

Glowing manifolds is very much a problem. You have a restriction in the exhaust somewhere. You should be running dual exhaust anyway.

Are you using a clutch fan? Looks good at idle but clutch may be bad and fan not really working while you are running. This was a common issue for my customers.

Check to make sure you dont have a 2 core straight six radiator. 3 core min.

Remember just because a part is new doesnt mean that it is working correctly.