If the plastic bag is not sealed I will guarntee parts will rust whereever the plastic touches the bag. Around here (northern Il) with the temperature changes moisture condenses on the castings even in plastic. I would suggest LPS 3 and then wrapped in a greased or oiled rag. If you then want to put in plastic maybe. It seems the interior of a plasic bag attracts and then seals in moisture so it cannot evaporate.

Vacuum sealed bags are an excellent choice.  For most of us that cannot vacuum seal the parts, then storing in a plastic bag in a temperature controlled environment would be on the list.  Condensation on iron parts in the spring and fall is the top item that must be avoided.  Second to that would be just keeping the parts clean until they are ready to use and keeping the critters out of them.

Lorena, Texas (South of Waco)

I am gathering up all the stock parts from the 57 Bird 312. What is the best way to store the cylinder heads? I have numbered and boxed the pushrods, lifters, rocker arms, cam, etc. Will the valves be okay seated? Vacuum seal bags for the heads to keep moisture out?

57 Black Tbird 312/auto