[Radman]

Chances are you just have a air lock in the system. Your heater hoses are looped so it makes it more suseptible to that. Remove rad cap and run eng. leave waterlevel down about 2 inches from filler neck. look inside filler neck when eng is running. if water is coming out of tubes then thermostat is stuck open. if there is no water coming out of tubes wait till eng warms up, watch gauge, if you have a 180 thermostat then at 175-185 the thermostat should open and you will see water coming out of tubes. If it just keeps getting hotter then the themostat is stuck closed. Reinstall rad cap, shut eng off, let eng cool ,replace thermostat. Refill with a/f, run eng with RAD CAP OFF till you know thermostat is opening and cycling. top off with a/f, install rad cap, fill overflow bottle to hot level marked on it. Shut eng off and let cool completly. eng may still burp some air out of system during cool down. make sure overflow tank still has coolant when eng is COMPLETLY cooled down. If not fill to cold level and run eng to make sure it is running on thermostat temp

That should take care of your cooling problems. If it still wants to run warm then the rad should be looked at. I hope you replaced it or had it rebuilt before running your new eng.