Help... cooling problem

Ok so I have a 1992 Mustang GT with gt40p heads, B303 cam, and a GT40 upper and lower intake manifold. The problem I'm having is that when i get on the car it gets REALLY HOT like pinning the needle on the stock temp gauge. first i tried bleeding the system, i ended up covered in coolant. next step was to remove the thermostat (even though it was brand new) and try a different radiator(both are stock) the car still gets hot but it cools down faster. i also noticed that the upper radiator hose has a lot of pressure on it(rock hard)i did a compression test just because it overheated and found all cylinders to be right around 120 psi or between 110 and 120. when bleeding the coolant system i seem to be getting never ending air but there is no oil in my coolant or vice versa. the car has the stock fan and a brand new water pump. i also dont get much for heat even when the car is around 175ish degrees... I'm at a loss because before i did the heads and intake the car ran kind of hot but never overheated, although the coolant was pretty brown when i took it out and the overflow was full of mud(i replaced that too. any help is appreciated
thanks
joe

i used the fel pro stock replacement head gaskets, i tried anything i could to clear the block out, including running about 20 gallons of hose water through the block from the heater core line on the front of the intake to the lower hose on the water pump. i have the stat removed which is why i am confused about the pressure in the system also.
thanks
joe

it seems to be a leak between the combustion chamber and the coolant passage, i smelled the air coming out of the radiator and it smells like exhaust... so thanks bullit95 for the insight.