NEED REAR END FOR 89

[FERGUS]

I NEED A 2.73 WITH POSI FOR MY '89 K5 BLAZER. I ALREADY HAVE A 12 BOLT 3.73 '79 REAR END. CAN ANYONE TELL ME IF IT WILL FIT IF I CHANGE THE GEARS? IF NOT, DOES ANYONE KNOW WHERE TO FIND ONE THAT WILL?