I've only swapped drives in the slim but from what I'm familiar with the PS3 should make you format the HDD. Each HDD when formatted is tied to that system so when you want to put it into another system is should format it again. Not sure why you're getting the restart the system loop but you can try getting to the safe mode and see if any of those options help.
https://support.us.playstation.com/app/answers/detail/a_id/1488/~/safe-mode-on-ps3
If you still want to swap you will have to download all your content again to the larger HDD after it's formatted.
https://support.us.playstation.com/app/answers/detail/a_id/1488/~/safe-mode-on-ps3
If you still want to swap you will have to download all your content again to the larger HDD after it's formatted.