273 Smoking When Cold....???

Could be all of the above. But do yourself a favor and change brands of oil.
I have seen too many engines totally sluged up inside because of Pennzoil.
I won't even use it in my lawn mower.
Before becoming a tool man 20 years ago I was the shop foreman at a GM
dealer for 13 years. We had lots of oil consumption problems when we
had Pennzoil. We switched to Northland (a local oil company that supplies
to John Deere Tractor Works). Our oil consumption problems dissappeared within a couple months. I have used Valvoline for years with great results.
I won't use Pennzoil, Quaker State, or Castroil. Changing brands of oil probably won't cure your problem but it could prevent problems down the road. Just my observations. Good luck. I'd look at the valve seals first.
toolmanmike