Fox Help

Not the best mechanic around by far but have some sense and experience.

Have a 93 fox. Inherited from a fam member recently passed. Its mildly built 302-bore to 306 and On3 Turbo kit installed. Trick flow heads, Megasquirt ecm

Out of nowhere, it started to overheat under normal easy going driving, so I shut it down.

Excessive pressure builds to the point the radiator has leaked.

No milky oil.. coolant and oil not mixing where I can see..no white smoke in exhaust...yet motor builds pressure and will overheat.

I learned the car doesn't have a thermostat. Bubbles from radiator that increase with temp increase of motor.

Chemical test was inconclusive

Head gasket? Water pump? Whats your thoughts.

Also. Heater in car not hot.

Yes I did the Chem test. Im positive I had coolant mix with the liquid.

Did another test later and verified no coolant entered the tube and the blue color did not change.

I bought a thermostat since when I got it. It didnt have one.

Also im replacing the radiator knowing it leaks so as for driving, I dont know it it overheats, however it does when idling in my driveway. When pressure builds, its enough where it will start seeping and spitting from the top hose at the radiator connection.

I've looked at all the pistons using a borescope and I haven't seen anything the makes me feel coolant has entered...no steam clean effect that I could see.

Thank you for helping.