we were typing ontop of each other.
i guess my assumption is your cooling system was designed for the 6, so it should work as is.
something is causing the hot engine.
get the oil changed and then drive it normally. monitor the engine temps.
1. while moving
2 while idling
200 temps are not uncommon. i have a 180 stat but the temp stays there.
get a 16 lb cap that was made for use with a recovery tank. like for a 80 camaro.
your radiator was designed to not be filled to the top. it was supposed to be filled about 3/4 below the cap. so if you do fill it to the top, when the liquid expands with heat then it burps when parked. that is normal. if you add a overflow tank then it burps and is caught and then recovered to completely fill the tank.
they should issue skate boards at wallmart. they always put what i want at the rear of the store. and then they make the super sized stores. 100 checkouts and 2 people to operate them. and 2 managers watching to direct you to the self checkouts. tom