I think if you used proper lubes on assembly, you can let one sit in most any stage for fairly long periods, as long as you protect it from dirt and such. Just be sure to pre-oil/pressurize with a drill motor a short time before you fire it for the first time. I, too, have had one sit in short block form for over two years, while I was doing other stuff and accumulating funds to finish it. I usually won't stuff one in the car, though, until it all is ready to be run in fairly short order.