cordless impact!! then finish off the bolts with a hand held torque wrench. THe cordless might not beable to pop loose and tighten bolts down very well, but they will run them out and back in ALOT faster than by hand. Plus, no cords or air is needed. Like I said, you probably will have to crack each bolt with a wrench, but then have the other person follow you with the cordless and run them biatches out fast! And like I said, it wont torque them over spec as most corless impacts do not have that high of torque rating.
Thats my advice... OH, and a BIG BIG help would be plastic bins, label the bins to where the bolts came from and place them in each bin. having one bin for the intake, one for the oil pan.... and so on, will make it ALOT easier to figure out where they came from instead of rumaging through a bucket full of misc. bolts.