Can I run two cabinets with this head?

Absolutely! The amplifier has two speaker outputs so build your own modular system. 

Plug one into the "bottom" speaker jack and one into the top. (Bass Block 802 are side by side.)

Note: On guitar heads, the "4 Ohm" Jack has a special contact that increases the amplifier's output. This allows you to get additional headroom. So when plugging in a single 8 ohm cab plug into the bottom jack. ONLY plug the second cab into the top jack unless you have a single 4 ohm cab, then plug it into the top.