Bitter taste of defeat! So much coolant in the oil pan.

Bad news everyone... it's not the timing cover and it's probably not the intake manifold gasket.

I re-installed the timing cover very carefully, then the water pump, etc.
After receiving my Fel-Pro composite gaskets in the mail, installed the intake manifold - everything lines up real nice on this engine and the gaskets were positioned correctly. Used RTV around the water holes.

I even let it cure over night, just as a precaution.

So just now I disconnected the overflow hose between the intake and water pump and plugged it. Then poured water/coolant into the thermostat hole and... it came out the oil pan.

It is highly unlikely that I managed to botch the intake manifold twice - I've done it successfully in the past. And the timing cover was taken out of the equation, at least from the water-pump side. The water did not reach the top of the thermostat hole - the leak is somewhere below the floor of the intake manifold as it now looks empty but liquid was still coming out.

The amount of water was the exact same flow - not pouring but not dripping either. It seems unlikely to me that after re-installing the timing cover and intake manifold, the exact same size leak would appear. So I think it must either be somewhere in a head, the head gasket, or the possibility that cylinder 1 got cracked somehow due to overtorquing a bolt that was too long or some such.

And now it's raining. Damn.