Same problem as always. Coolant in the oil.

I take it you are tearing it down.

Here's an idea.

Remove intake. Turn upper rad hose straight up.

Grab some thin steel/aluminum plate, use intake gasket as template, cut out four pieces large enough to cover the end water opening of the heads, drill holes that use the intake bolts, install plates with some silicone, seal it up, let set and fill the radiator. If it drains down, it isn't your intake sealing.

This will also give you an opportunity to see if the water is leaking down the valley from the head gasket. May also allow you to see where the water if it's coming from the front.