Thermostat, Radiator hose, clogged radiator, bad water pump.
Change the thermostat and make sure the bottom hose is not collapsing first. Its not common the hose is bad but it happens. if that don't fix it I would check the radiator. Then put a water pump on it.

If I ain't mistaken and I could be. The thermostat because of how it goes in and where it is at is easy to get in them backwards so I would check to make sure its not in wrong. Friends truck was doing the same thing because someone had put it in wrong.

 

ask up in the stroker section, somone up there might know. the idi and strokers are different. could still be same issue, but different parts.