Hi - Hoping you can help me ID what model and year Jag this diff came out of.  I've asked Daze but figured I'd try this forum.  My need is to replace pinion seal now (need to stop leak for inspection) and wil be refurbishing it this winter as it has been in a car since 1988 and could a look through, so need info for parts.  Based on my research:
- Salisbury differential (drain plug in rounded case bottom, round pinion flange)
- Flange-to-flange width exterior-to-exterior is just under 54" 
- Bottom front right corner flange of casing stamped with:
     L   71
           A 
      1071
- Bolt tags on cover are 46/13 for 3.54 indicated gearing, and "P" for power lock - both wheels spin together
- Dual coil overs each side
- Inboard brakes
- Casing forged with C4HU-004-25
- I have not dropped the stub axle yet, or checked the side axles, so don't know if bearings are ball or roller. Will do that when I get there.  

My guess based on this is it is a Series 1 diff from an XKE, possibly manufactured in 1971 (maybe October?) if the stamping is any indication, so maybe a 71 or 72 XKE? Or maybe the stamp is meaningless as this does not match Daze's table for year, width and ratio, the Wiki site table would make it a Series 3 XKE, or S-type or 420 based on track width, and the widths in blog phrog's table are 52" for XKE (1961-75) and 55" for S-Type (1963-68) and 420 (1966-68). Interesting data, but it varies from source to source, so I'm not sure. 303Radar indicated in a Jag IRS blog 11/14 that if 54", it is XKE.  Is there something else to look for?  FYI: It is in a 1980 Arntz AC cobra kit I bought out of an estate so no history, other than kit was bought mid-1980 and finished 1980-89. 

Thanks for any guidance you can provide.