How long can an assembled long block sit covered in a bag for?

I bought a 383 LT1 and I am going to finish the last part of the valvetrain - rods, rockers arms and rocker stud girdles. How long can I let the engine sit like this if I install everything correctly - well lubricated with oil and the whole works? I have a lot of parts to still collect and dont want to worry about problems later from letting the engine sit for a few months. I bought it because it was a great deal and now I need to get everything else for the car - drivetrain and suspension.

The previous owner was a very knowledgable person who build most of the long block and had machining work professionally done. Anything I should check, and how can I check it?, before I trust that the engine is assembled right and to continue with the wiring and accessories? Crank rotates fine and smooth without binding of any kind.

Appreciate the help. This is my first engine build (i am really just finishing what was started...)

 

It can sit pretty much indefinitely. There's not a lot you can do to check it out without taking things apart.