Do you have an open or closed drive shaft? If it is closed and you want to keep the rest stock get Patricks 3:55 kit. That will cure your problem. My 46 Burb has a 3:53 which is perfect. I had a modern rear end narrowed with larger brakes for both my Suburban and my 41 1 Ton pick up.
If you change rear ends you will have to deal with width, brakes and hand brake cables that will be different.
