Measuring offset for Wilwood rear disk brakes - help

In the process of upgrading to an 8 3/4 rear end. Mine has been shorten - I do not know if it came from an B or C body. I plan to also upgrade to disk brakes, going to wilwood to match the front brakes

When I measure from the Axle Flange to the Axle housing my offset is to small for the Wilwood options (2.36, 2.5 and 2.76). My measurement is 2.20"

Am I missing something? If not what options do I have to either shim or something else

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