Help! My truck puked in the cold. Is it dead?

[freemonty]

It's really cold here in Chicago (negative 15deg) and I tried to start my 71 Chevy C10 pickup (350cu) yesterday and it turned over, sounded terrible and ran for 10 secs then shutoff. It was clunky and really rough. Tried a couple times, same thing and I gave up. Then today I noticed underneath the truck that it crapped a bunch of oil, a whole bunch and it looks like it came right from the oil filter. I decided to change the oil to see if anything happened and sure enough, I got a little bit of milkiness. I didn't notice any issues with the block when I was under the truck and the oil filter looked to be intact when I removed it, so I don't know where the oil came from. The coolant level was OK when I checked it. The oil on the ground was a significant amount, though I still got several quarts out when I drained it. The biggest oil spot was directly under the oil filter and then it spattered backwards (as the fan blew it towards the rear of the truck).

What happened to my truck? I put fresh oil in there, but I'm afraid to try to start it again. It was running great before this.