I'd say don't try to just clone the drive and boot from it. If the models are (chronologically) far apart, it's possible you'll run into issues that way, particularly if OSX on the older machine was installed from the machine's OEM disk, rather than a retail copy of Tiger.
Best thing is usually to install clean on the new machine, and then transfer your stuff over during install, when prompted (using target disk mode on the older machine, as described).