or a .030 overbore for 406 cubic inches (

). keep the compression ratio low and you'll be able to crank the psi up. then you can add nitrous oxide on top of that.
back to the OP, they store them on their shelves for gods know how long before they ship them, so if you keep them in the original boxes then you will not have a problem. keep them dry, away from direct sunlight, all of that that you would do normally with anything that is going to be stored for a long time, and you'll be fine.