0. Make sure you have the latest Mac OS X (10.6.x)
1. Install DarwinPorts (
The Original DarwinPorts : Open Source Packages for Mac OS X)
2. Open Terminal.app and execute
sudo port install p7zip # (enter your password when prompted)
7za e /path/to/manual/370Z_Service_Manual.7z
You should be able to open any of the PDF's with Preview.app. This has nothing to do with Mac vs. PC, but just old software.