Hi Steven;
Yes, your most likely speaking of Helm Publications. The Z360/600
manual is really a supplement manual to the Sedan 360/400/600 manual, which
gives all the early sedan items and much further brake down of larger parts.
And both will be needed if you are working on a April 1971 Sedan or later.
The Owners manual is ok, but it does not include the original plastic cover
or the maintenance manual unless it is updated since I last spoke with them.
Original Sedan shop manuals (or Big Blue) as they are more commonly known.
Are available in fair to Good condition for about the same amount. The
original manual's paper is better and they come with a loose-leaf locking
binder.
Bill