Pics please.

I’ve got a quick question. I have a 83 gs550L rear wheel that I plan on throwing on my savage project. Can I still run the belt drive or do I need to do a chain conversion?

I have that wheel on one of my bikes and it goes right on, with the s-40 drive hub and brake. I still run the belt. Just don't go crazy with the rear tire, the 16'' rim will take a bigger tire than will fit on a stock bike. Check the od of the new tire BEFORE you buy it and compare against yours. With just a 2.5'' wide rim you won't want a real fat tire.
I run both Kaw pulleys which moves the axle back some and gives me plenty of room for a Shinko 240- mt90 16. My rim is also tubeless, thou this tire is not.