Sorry to spoil youe excitement, but this is what the results mean:
If both wheels were free and you had a 5.14 ratio, you would be turning the driveshaft 5.14 times to get the brake drum(s) to turn 1 turn, if they turned at the same rate. Since however you have one blocked, the brake drum does twice as many revolutions. Therefore with 5.14 revolutions of the driveshaft, you would get 2 turns of the brakedrum. For 1 turn of the brakedrum, you need 5.14/2 tuns or 2.57 turns, which is what you have observed. You have a 5.14 rearend.