Your problem IS bad oil: it has water in it. You have either a head gasket that has failed, a cracked cyl. head, or cracked block (unlikely). I don't know the history of your motor so I won't comment, on how it got that way, other than to say that I am very sorry to hear you have such a problem with your V10. Best of luck to you.

others - Yes, the 300 straight 6 was a great truck motor: not a lot of power, but tons of torque, and bulletprooof.