[stevie 77 930]

Typically, timing should be checked @4000- 4500 rpm (vacuum lines disconnected) with a range of 26-29 degrees of advance depending upon other tuning factors.

http://forums.pelicanparts.com/911-engine-rebuilding-forum/122632-930-ignition-timing.html

http://forums.pelicanparts.com/911-930-turbo-super-charging-forum/456377-ignition-timing.html