freeze plugs?

[Mr 5 0]

A few thoughts:

Have you installed the correct water pump? You may have a WP with the wrong flow direction. It happens, as there is a similarity in 302 water pumps and sometimes the part guys can give you the wrong pump. If so, you'll overheat.

Is the fan working properly? You didn't mention replacing it and the factory fan is known to fail, usually from loss of fluid. That will cause overheating.

When you replaced the factory 2-row radiator did you replace it with a 3-row radiator? If you install better heads temperatures go up a bit and the factory radiator is just adequate for the stock engine. You need a 3-row radiator for best cooling.

Were the new head gaskets installed properly? Any leakage? Any leaks anywhere?

Does the radiator steam or is it just the gauge going up?
Do you still have the factory gauge? Replace it with an aftermarket gauge and a new sending unit. Factory gauges are notoriously unreliable.

As I said, just a few thoughts.

Hope you can find this problem and hope this has helped.