I am a newbie but I thought when you put Mark IV heads on a Gen VI block there was a specific gasket you had to buy??
Yup...I also said to use a Fel-Pro Q10751 head gasket when swapping parts around as well as Permatex sealer on the head and intake bolts. Hopefully, it gets fixed.
Found out today that they used a Fel-Pro 10751 head gasket and put permatex on all the head bolts as well as all the intake bolts and all is good...no more water in the oil. Running like a top.
I bet it was intake to head. Had that happen before.
Congrats on getting it going. Now time for fun!
I think you are right. I was told that ome of the bolts in the intake side of the head went thru into the water jacket. They got it going and running with no issues now.