Having issues burping the coolant in my z. '86 na2t.

I burped this b**** a few weeks ago with no issues like this. I hooked my spillfree funnel up, filled coolant, and warmed the car up until bubbles stopped coming out while topping the funnel off with more coolant.

Then I had to pop the radiator out really quick for some intercooler pipe routing. Threw everything back together, tossed my funnel on, filled coolant, and warmed the car up, but this time after it warmed up to operating temp the funnel started violently boiling and spitting coolant ALL over my s***. Mind you I only had 1/4 of it full of fluid to start.

So I thought maybe the thermostat is going out. Took it all apart, replaced thermostat with a new working one, threw everything back together and threw my funnel back on. Filled the coolant, warmed the car up, and it still wants to violently boil out all of my coolant instead of get the air out.

I cannot properly burp this system because it will push coolant out of the funnel and spill everywhere.

I know it's air in the system because the heat works quite well while I'm moving, but at a standstill the heat rarely works. I took a few lines off here and there and felt no major restrictions to the flow. Let's also assume my head gasket/compression is fine considering I'm not burning any coolant, both the oil and coolant are perfectly clean, and the radiator hoses are squishy when cold and firm and fully pressurized while warm. I know my water pump works because I hear coolant sloshing around when I turn it by hand.

On my morning drives to work, I will have a fairly empty coolant reservoir and by the time I arrive at work the reservoir will be half to 3/4 full

How can I fix this?

Get the nose of the car up higher... Are you sure you don't have a crack in the reservoir, and is the overflow hose intact?

Also, see procedure at 6:00 in this vid: https://www.youtube.com/watch?v=GDs_h2sGWLo

If in the course of chasing the issue you let the car come up to normal temperature with the cap still off it can be normal to boil over, the cap gone has the pressure at atmospheric and then the coolant boils at 212..........add cap and the boiling stops.

Maybe that is confusing the issue somewhat.