Coolant building too much pressure

block looked alright. I tried cleaning it up and didnt notice any cracks or whatever. I had it honed and cleaned but never had it surfaced. It looked alright. That was done at klispies.
Thermostat is new. I even tried running without it. The stock temp sensor is right next to it and that is new also. I should move where I have the megasquirt coolant temp sensor. I have it on the return right before the water pump after the heater core, oil cooler, turbo.
I got the felpro mls headgasket and used the copper spray on it.

And how do you go about bleeding the coolant? And what exactly does that funnel thing do?

I’ll start it cold. so maybe around 75-80 degrees then in a few minutes this happens. I dont think it even gets up to normal operating temp.