Well from what I surmise.
I have seen many 3.8 Ford motors looking like that. Usually not SC's though.
I bet he definately used a non detergent oil (never a synthetic for a fact)
The head gaskets are 100% original
And he definately ran hot when he blew the gaskets however that wouldnt lead to what we are seeing here.
Infrequesnt oil changes especially witha non detergent type oil can cause that and before he bought the car with around 50,000 who knows how often it was changed(currently over 100,000).
A malfunctioning PVC system can add to the problem as Dave has said but again the use of a non detergent oil and perhaps unfrequent oil changes before he bought the car may be a culprit.
Anyway my biggest fear is two many chunks dont get into the oil pan (possable pickup blockage). I think we can take care of it with little hassle unless he REALLY Over heated it and did something bad to the shortblock.
I have devised a plan using a 6 hp shop vac and lots of patience carb cleaner and oil to assure i6t goes as smooth as possable.
Worst case scenario he has a terrable rod knock and it needs to get rebuilt.
Thsi pictures my freind is why to use a good oil and change it!!!! As well as makeing sure your PVC valve is functioning properly.
Car did run good though till it took a doo doo (looks like it tok one too eh?)