Finding the package aka 5.1.7 for Lion was hard enough. But then the installer complained like this:
„Safari can’t be installed on this disk. This volume already has a newer version of Safari installed“
Ok, let’s delete Safari 6 from the Application folder. No luck. Still complaining. Terminal to the rescue. You need to delete some more files:
sudo rm -rf /Applications/Safari.app sudo rm -rf /System/Library/StagedFrameworks/Safari sudo rm -rf /System/Library/PrivateFrameworks/Safari.framework
Now 5.1.7 installation worked like a charm.
As usual, I would not recommend to do this on your main system. Some virtualization software is just perfect for the job.