Why does my iPod show only 80gig after I installed a 160gig?

I replaced my 80gig HDD with a new 160 gig HDD. After restoring it, It only shows 80gig available in iTunes. I tried formatting it in Disk Mode, with Disk Utility. And I verified that there are no partitions. But that didn't help. What else can I do to help it see the new, larger drive?