Overheating Issue
 

My engine swap is complete on my 94 f150 but now I have a overheating issue. I rebuilt the 351w engine from the block up. Engine has 25 miles on it. New everything, hoses radiator, water pump, etc.... It takes the engine about 10 miles for the gauge to gradually heat up over up to 3 quarters mark. I'm running a 160 thermo, no leaks, no water in oil, this is driving me crazy. I am running serpentine belt pulleys on a carb motor. Please help.