I don't know what the speaker is in your combo, but as long as you can plug in a head, I don't see why it wouldn't work. I have an old Acoustic 126 combo that has a vented 15" speaker and I sometimes power that with a 320 head. It sounds far better with the head than it does with the amp in the combo.
Cranky old man. Cranky old bass. Cranky old amp.