Overheating headache

alg said
It overheated the same but lower temps. I replaced the radiator and added an NOS fan shroud. That was four years ago. I’ve hardly run the car since. These numbers are at least 20 degrees higher. I am going to measure the fan tomorrow, but it is a more stout fan than the original.
When you say tune related that refers to timing? I haven’t checked that. Could headers cause excess temps more than stock exhaust manifolds? I bought this car new, and the timing was always TDC. Will have to address this too. Could headers cause excess temps more than stock exhaust manifolds and dual exhaust?
I have some work to do.
Thanks for your reply.

The headers themselves will not be the problem; but if they were hammered nearly shut, to make them fit, they would hold back exhaust flow and could, mind you "could" but probably not increase engine temp in various spots. This is a reach, and you would likely have other drivability related concerns as well. So, let's assume the headers are out of the equation. Is it possible the thermostat got put in backwards? Is the fan on a clutch or direct bolted to the water pump pulley? I've seen bad fan clutches cause lots of overheating issues. Did you say the engine was rebuilt? By whom? I don't want to knock anyone's work without seeing it firsthand, but could be warped heads, deck surfaces, bad head gaskets, everything else that has been mentioned, etc. By tuning, yes, I was referring to ignition timing / fuel mixtures. Let's start by watching the coolant with the radiator cap off. Do you see any flow, after it is warmed up or does it erupt / boil over right away? What does it smell like? What color is it?