Subaru Repair: 94 Subaru Legacy engine temp, coolant temp, head gasket

Question
Recently replaced head gasket, water pump, thermostat, radiator and temp sensor, and had heads milled, due to overheating.  Temp gauge intermittantly goes 3/4 of the way to Hot. Had a friend use his heat gun to check the actual temp of engine. One side of the head (block) reads 180 degrees, and the other is reading 140 degrees. When the temp reaches 3/4 of the way to Hot, fans are running... Thermostat is in correctly. Any suggestions as to why this is happening..advice?   Thanks!

Answer
Not Knowing how long ago the work was done i would say if it was just done you have an air pocket in the cooling system.Also a temp reading should be done at the coolant temp sensor to know what temp the computer thinks the vehicle is running at.And at what temp the computer first turns on the fans.