Overheats

I have the car listed above (cam) I bought it and didn't even make it ten miles before it overheated. So I got it home and changed the water pump, the thermostat, and overflow tank (which is where you put the coolant), still overheating.

I took the thermostat out to see if I just got bought a bad one (somebody told me "I didn't really need it" not sure if that is true?).
But it overheats I had some kinda coolant pressure test done and it didn't lose any pressure, it's not smoking white, nor is the oil milky.
I have bled it like three times flushed it three times all of that.
I have just been messing with it and realized that at an idle it will overheat with no heat but if you rev it to about 2,500/3,000 rpm's it cools back down with heat, but if you go to drive it, it will bubble all the coolant back out the overflow tank. Can anybody give me some help?
Please, and thank you.
#Aaron.