What kind of water pump and belt/pulley system do you have? Did you go to a serpentine with reverse running water pump? Did you get the right direction water pump?
And if I read this right, the temp goes to 215-225 after short drives. I even read about a "pegged meter". That's not comforting if I want to go for an all day drive. To try and let him think this is normal isn't helping. The cooling system should be able to fairly stabilize the temp within reason. 30 to 50 degrees in either direction is not stabilized to me. The water temp will go up after shutting the engine off because you have stopped circulating the water. Is that when your gauge pegs?
