Engine is spitting anti freeze through catch tank

[michel schryer]

I have this problem with my anti freeze spitting out my catch cylinder tank.
My engine is a 302 5.0L with gt40 heads and a mild E303 cam. The cap is screwed on a CSR 45 degree aluminium elbow which is mounted on the original housing. I installed a big braided hose from the CSR housing to the top hose of the rad and noticed that the middle part of the hose is slightly above the thermostat filling point where my cap is creating an air pocket. Takes me forever to fill the system. Could that cause the system to overpressurize. I think the rad cap is 10 or 15 psi.
I guess i have too much pressure in the system and at some point it spits out the anti freeze. My catch tank is just a small cylinder that vents to the atmosphere. I changed the rad cap which is not on the rad but on the thermostat housing and it still spits it out. Could i just remove the thermostat and hope it solves the problem or it's the hose that is too high. Those CSR housing are not cheap and don't really want to buy another one, need some advice here, thanks !

Michel