Replaced headgaskets on 3vze, not have an overheating problem.
It seems like there is no water circulation. Tried with two different thermostats (new and old one). When you start the truck, the water temp just keeps rising till it boils over. Any ideas why this would be happening?

 

airbubbles likely trapped.

Take the thermostat out to see if air is the problem. If it runs cool, then you know where the problem is.

 

Sounds like you still have air in the system, did you bleed the cooling system with the front end of the rig higher, and the heater control full on?

 

If that doesn't work, did you put your head gaskets on backward & block coolant flow?