on my 88 GTU i can adjust the timing just fine, but on my Turbo II there is now nut on top of the CAS so how do i adjust the timing?

 

unscrew the nut and twist the cas.
Just remember when you change the timing via the cas ALL timing maps get changed.

 

NO NUT ON TOP OF THE CAS
so how do i loosen it?

 

the nut is on the side of the CAS towards teh p/s pump and a/c compressor. It's kinda set down so it's a little bit hidden. Try looking straight down from the oil fill cap area. Oh yeah, the nut also has a little cap on it, so... look hard.