thunderbolt 3 device to firewire 400 port?

This is probably a ridiculous question, but I've searched the web and could really only find people wanting to connect an old Firewire device to a newer computer's Thunderbolt port. My dilemma runs in the opposite direction...

I have an early 2008 Mac Pro which I plan to replace with a newer iMac within the next couple of months. I'm looking to get a UA Arrow Thunderbolt 3 audio interface to use with the iMac, but wondered if I get the interface early if there's any way to hook it up to my Mac Pro to try it out and get used to it. My current audio interface is FW400 and 10 years old, so I plan to retire it.

This Mac Pro doesn't have FW800, only 400, and some (early generation?) USB ports. I wouldn't be worried necessarily about taking advantage of the Thunderbolt speed at this point, and so hoped there might be a cable adapter chain I could use to make it work in the meantime.

I'm sure there are all kinds of architectural reasons this wouldn't work, but figured I'd ask just in case...

Thanks!