I have timeserted all 8 cylinders on my Expy. The use of air tools is preferred due to the slower rotational speed of things like the air ratchet and what not. But, if you can get a drill that only spins at say 150 RPM, then that will work too. The other advantage of the air tools is the 90 degree operation that most of them work at. But, if you can get an angled drill, then that will work too.
LIke was mentioned, if you are doing it with the heads installed, GREASE, GREASE, GREASE!!!!! I would also recommend getting some smaller tygon tubing and using that to hook up to a vacuum so you can sweep out the cylinder after all is said and done.
When it comes to rotating the engine, what I used was a 10 amp momentary switch with about 18 inches of wire and alligator clips on the ends. Then you can remove the cover off of the starter solenoid and connect the switch to the battery side of the starter solenoid and to the small post on the bottom. Then, as you depress the switch, the starter will be engaged and rotate the motor. You don't have to worry about the engine starting since you shouldn't have the keys in the ignition.
When I did my engine, I removed the heads as I wanted to fix the engine all the way and not have to worry about this again. THis also gave me a chance to port/polish the intake to get some more power out of the engine.
So, if you have any questions, let me know.