This Mac OS X Install Guide is really outdated. When using a Recovery disk to install Mavericks, OS X just told me it couldn't install Mavericks. Didn't tell me why, it just told me it couldn't do it. I did something like this:
1. Get a USB or Firewire HD enclosure. Use the iFixit HD Replacement Guide to put your new HD into your iMac and put your old HD into the enclosure.
2. Plug in the enclosure and its USB or firewire cable to your iMac.
3. Hold down the option key on your keyboard and turn on your iMac. When it boots, it should recognize your old HD in the enclosure and give you the option to boot from that drive. Select that drive. It's just like booting when the drive was still in the iMac but maybe a little slower.
4. Now go to the App Store and Download and install Mavericks. You'll need to select "Show all Disks". You may need to use Disk Utility to format or erase your new HD if it doesn't show up. Use Migration Assistant to transfer apps and data from your old HD to your new HD in the iMAC.