Car overheating

If head gasket is not the problem and was put on correctly then when it gets hot feel for cold spots in radiator when fan is disabled, if you feel any then the rad is bad

Are you sure that you burped all the air out of the cooling system? Make sure you have the heat on when bleeding the system. Do you have a scan tool that tells you the actual temp it is running? Both fans should turn on if it gets too hot or when the a/c is on.

If it's boiling then try replacing the cap and see if that helps. If it's not holding pressure then coolant can boil. If it's really getting hot then both fans should turn on.

Did you burp the air out of the system?

Are you sure it's boiling and it's not bubbles from combustion gases getting into the coolant. I know you replaced the head gasket.

Try this to be sure all air is out.

Remove cap, start engine and turn on the heat, let idle till it warms up, When it reaches operating temperature begin raising the idle up to about 2500 rpm and hold for about 5 seconds, do this a few times while watching your coolant level in the radiator, be sure you have heat at idle, till the bubbles subside and the level is good, then return cap and the system should be bled.

You could have a crack in head that was missed if it still overheats and all that stuff was replaced or if it heats immediately then it may have the tstat in backwards. That is about it if everything has been replaced, etc.