Cam break in during cold weather?

I have a very mildly built / freshened 360. (FLAT TAPPET cam + intake, 30 over pistons and a few other little things) I want to break in my motor tomorrow or Monday. The day time high is predicted to be 35* F. My friend told me that this may not be a good idea but I wanted to get more experienced peoples opinions. Is there a larger chance of failure?
Thanks
David
Stop the paranoia and fire it up LOL all of us start worrying about all the things that could go wrong...
It usually has something to do with all the money we spent.