8 3/4 rear casting 1820657

Thanks for the info. Since it's an open rear (non posi), what I did was turn the drive shaft and watch the wheel turn one rotation, but because it's an open rear and the other tire does not move, I rotated the wheel twice or 2 turns because of the spider gears multiplying it times 2 with one wheel not moving. The ratio that I came up with was about 3.6:1, which would be pretty close to the 3.58 that's stamped on the carrier. The only thing is the listed ratios I found are: 2.76, 2.93, 3.15, 3.19, 3.23, 3.31, 3.36, 3.55, 3.73, 3.91, 4.10, 4.56, 4.89, 5.17, 5.57. The earlier rears were the only ones stamped with the ratio (no tag).

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