water leak

The above questions are good to answer...

Did the machinist shave the heads? If so, the intake needs to be machined too to make things line up. And did he mill the block surfaces? If done poorly, it cold throw the head angles off and open up the seal to the intake. Ditto for a poorly machined head. BUT is the 30000 miles all since the rebuild? If so, and then this just started all of a sudden, then the machine work is not likely the cause.

A Pint or a quart? Whoa! Stop driving and drain the oil from the pan like AJ said above to see what comes out. Watch the first stuff that comes out carefully, because the water will be on the bottom.