I have a chance to pick up a 727 from a 70RR that was rebuilt about 2yrs ago to stock specs, but never installed. I know the seller and he showed me the receipts, so I don't doubt the condition. The pan was loose so I could look inside and see it was clean/dry.

What is the "shelf life" for a 727 rebuild, that is, sitting dry, how long before it should be rechecked?