Installing MacBook Pro 15" Unibody Late 2008 and Early 2009 Dual Hard Drive - iFixit Repair Guide
2008 MacBook Review: Better than a modern MacBook in many ways
How to Upgrade MacBook Pro Hard Disk, Late 2008, 15-Inch: EveryMac.com
How to add a fast new SSD to your old Mac or MacBook for only $150 - 9to5Mac
Install an SSD into the optical superdrive slot on a MacBook Pro | OSXDaily
RAM upgrade and/or SSD drive – what's the benefit?
Even after 12 years, my late 2008 MacBook Pro hasn't given up. Upgraded it to 8GB of ram, added an SSD, and patched it with MacOS Catalina. Still use it everyday. :