In my current system I had a 130 gig SSD that was used for my Windows install and a number of other items. My secondary drive was a hard drive that had my games + game files and a few other items. My SSD was getting filled up so I transferred my SSD information to a 500 gig SSD via a USB 3.0 Adapter to SATA. I never touched the hard drive. With the new SSD everything booted up fine and my hard drive information was all there; I can access my games without issue.
Long story short: You should be fine. If there are any issues check your BIOS to see if the hard drive is recognized.
To be safe I strongly suggest you back up your information to an external hard drive such as a Western Digital Passport or a Seagate Backup Plus Slim. I have both and they do the job. Staples had a very nice sale on the Seagate.
I hope this helps.