Cylinder head question (Dart)

[Belgian1979]

Some of you may have followed my previous threads. The heads in question are Dart Pro 1 215's.
I started to disassemble my heads in order to have them redone as I suspect the guides to be bad (always had oil consumption)
While doing so, I noticed that the exhaust crossover passage in the heads (so the center passage) which I do not use as none of the manifolds I use have an exhaust crossover has oil in it. I first though this was water, but when going in it with my finger it turns out to be oil.
The exchaust ports do not have an opening that goes into this crossover channel.

Can someone explain to me where this oil is coming from? Rocker stud bolts (in this case the bolts from a shaft rockers system, exhaust,...???
Worried here.

[mag2555]

I was at first thinking that your casting could be cracked or pours in that area thru to under the valve cover, but I then need to ask if your seeing this on both heads, because if so then I really don’t think that’s the case.

Do the plugs out of those two cylinders with the heat crossover passage look more caked with oil then the others?

[Belgian1979]

I was at first thinking that your casting could be cracked or pours in that area thru to under the valve cover, but I then need to ask if your seeing this on both heads, because if so then I really don’t think that’s the case.

Do the plugs out of those two cylinders with the heat crossover passage look more caked with oil then the others?

Both heads the same and no difference in the plugs. In fact number 6 is the best one out of all. But that may be because of other reasons.

Meanwile, I also noted that the alu plate of my rev kit protrudes a little on the underside of the driver side head. The gasket was also wet on the underside

[Belgian1979]

[Belgian1979]

BTW: the gasket is a 1206S gasket so with a steel inner layer as the engine kept pulling the gasket out on the center wall area between some ports on decel (15 - 20 kPa)