How long before new/rebuilt engine needs primed again?

Picked up the 340 a couple weeks ago and the engine shop primed it right before I picked it up. I intended to put it in that weekend; however, due to some transmission issues and other stuff it didn't get done. How long can it sit on the engine stand in the garage before I need to reprime it? It should be going in in the next couple of weeks.
Author: admin