nik,
i have always done this adjustment on a level car without using a jack..the '77 and later tranny uses a 'helper spring' on the tranny end and you have to use a feeler gauge to set it correctly. it actually removes the 'guesswork' of setting it like you have to do on the earlier cars, but like a said, a picture will be worth a thousand words for you. wayne's '101 projects' book outlines the procedure, but i'll bet a search would reveal the same info..it may even be in the 'technical arrticles' section of this board. clutch cables were designed by porsche to be easily adjustable..don't dig out that checkbook just yet! if i get a little time, i'll see if i can find the detailed procedure, and i promise it won't be complicated.
ryan

nik,
read up on this:
http://www.pelicanparts.com/techarticles/911_clutch_cable/911_clutch_cable.htm

ryan