From a safety and performance standpoint drums will be more than adequate. The only reason to swap to discs is ease of maintenance. If that is your desire there are lots of kits available. I've seen them on eBay for about $350.
I have used SoT's rear disc brackets on 2 rear ends. The work perfectly, allowing you to mount 04 cobra rear disc brakes and have a working parking brake. Been running them on my daily driven 68 for about 2 years now, no issues.
I have a used set of brakcets that will work on your 8" rear end that I will sell. PM me if you want more info on that. I upgraded to a big bearing 9" so I had to get new brackets. These are just sitting around.
You don't have to replace the bearing to install these brackets either. They slip over the shaft and bolt right up.