Geoff,
Fairly simple conversion ... just unbolt old, install replacements, and get alignment afterwards.
Here are a couple of scans that may make it more clear. First is the hydropneumatic setup, second is a coonversion kit that was available in years past. Any '78 or later struts would take the 90 mm ear spacing of your 'S' calipers, or later 'A' calipers.
