I need to figure out what type of gears that will fit a 1990 fleetwood cadillac?

I need to find out what other gear set ups would fit the 1990 fleetwood brogham cadillac mine slipped a pin and shattered them. Please help|||Just about any GM rear end will bolt right in that car. I'd hit a junkyard with $100, and see what's out there.|||In a car that big, I wouldn't go much smaller than 3.70:1.