Yep, what he said...
If you prime it out of the car, you need to make sure that you'll have it back in the car and ready to crank the same day. Otherwise, your efforts will have been done in vain...
I cannot emphasize enough, just how important proper priming and cam break-in is for these motors. They inherently wipe cam lobes at start-up, usually do to improper break-in prep. Be sure you cover all lobes and lifter bottoms with Comp Cams moly lube, or a good equivalent! Use a bottle (or two) of GM EOS mixed in the oil too.
It's easy enough to prime the thing in the car with a speed wrench handle, adapted to a priming tool in the Cam Sensor hole. I've done it many times, and the only real side effect is a tired right arm...
Also, make absolutely sure you have the Crank Sensor in the correct slot, before trying to crank the car. Doublecheck all essential sensors to ensure it'll crank.
You really need the thing to start immediately, and build oil pressure thereof.