Our van was using coolant, and it was entering cylinder #1. This was due to the the lower intake and plenum leaking. It is still difficult to get coolant into a Series 1 3800.
I knew our van was never over heated. Amazing how people will keep driving with the HOT light on for miles..I bet TechII has seen that a lot as a tech mechanic.
I also wonder about the rings and cylinder walls being scorched from overheating. I guess you would have told us you were burning oilo and loss of power even.
You should strongly consider getting the heads re-conditioned if you are going to keep it. I am not certain if they will have to magnaflux the heads for cracks, but they will have to be checked for warping and be re-surfaced. It may be easier to get heads already done.