Last year I had a similar situation on my 427 sideoiler. Slight condensation on the
oil breather on the valve cover, etc. Then, all of a sudden the left bank sidepipe began blowing white (steam). Of course you know what that meant...either a blown head gasket, cracked head, cracked block. I pulled each plug and shined a flashlight into the hole and walla! There was a nice puddle of
antifreeze staring back at me from the top of the piston in the back cylinder. Lucky for me, it was only a blown(leaking) head gasket. The 427 is known to have a weak spot between the end cylinders and the waterjacket ports, because the large bore leaves so little space between the bore and the waterjacket port.
So I pulled the engine and decided to take advantage of the situation and replace the clutch and flywheel (resurfacing). Pulled both heads and had them checked for flatness. The oversized Manley valves and springs were fairly new so we just cleaned up everything a little and reassembled it with a set of Fel-Pro head gaskets.
Its really not that big of a job once you get started. You could do it without pulling the engine but I didn't want to take a chance on scratching up any paint or brightwork. Just make sure you retork everything in the proper order to the proper specs.
Bet you have the same or similar problem. If you keep driving it, you will probably also begin to blow steam. It starts out with just a little puff of white. Within a few miles it will start to puff pretty good. But you really don't want to drive it with
antifreeze in the cylinder.
Good luck, Bob