I would've tried it already if the rental places here offered one.
Home Depot has a Rigid impact wrench w/ up to 700 ft. lbs., but I'm not
quite desperate enough to throw down 200 clams for one use. I'm
looking at used tools on Ebay now. There's a Chicago Electric Power
impact wrench that claims a max. 400 ft. lbs. of torque. Looks like I
can get it for around $30.

I agree that Chilton's is crap. (1. Disconnect negative battery cable
2. Overhaul Engine) I might also submit that, if indeed Helms is the
best manual, their marketing department needs some work--never even
heard of them.