One thing I forgot: Volvo suggests that if you don't want the car to spark (like when checking compression) disconnect the red-white wire on the coil. This way there will be no spark. When I personally do a compression check, i just jump the starter solenoid to the positive terminal of the battery. The only small wire on the starter motor is the right one. You may not want to be under the hood when you try the bump starter method. Anyway, just FYI.

 

I just got done going through the engine on my 740, and tightening the harmonic balancer bolt is MUCH easier with the 'special volvo tool'. It's not very expensive and once you get it you don't have to remove too much stuff to put it to use. I would highly recommend that tool as I didn't want to risk making a relatively straightforward mechanical task any tougher than it needed to be. Good luck!