[Mike_The_Grad]

Just throwing this out there, but have you "burped" your cooling system real well? I had no clue it was necessary when I freshened up my motor. I found out pretty quick my ole factory gauge still works spot on as does the sender. I had a couple of air pockets built up that would send my needle almost full tilt after about 30 minutes driving. Not knowing it was air at first, I pulled the thermostat thinking it was stuck. It worked just fine on the stove in a pot of water. So I read that you can drill a couple of 1 1/16" holes just inside the sealing surface of the thermostat. It helps purge most of the air as you fill the system as long as you give it time. Another thing I did to burp mine was to back down one of the loading docks behind my work and pop the rad cap while it idled. Those docks had a nice incline to them and worked perfectly for getting those last little air pockets out.