From what I can recall, we've never addressed the rubber mounts before. It certainly will help to get a good idea of the thickness of each one.
By looking at the parts manual, there are different part numbers for the thick rubber shims (as they're called in the manual). And to compound the issue, from 1977 and up, they modified them slightly. At least that parts manual will give you an idea of which ones are supposed to be the same and you can judge which ones are showing more wear.
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From Feb-77
This is the page of the online parts manual for vehicles built after Feb-77:
http://www.carpartsmanual.com/nissan/pa ... rom-feb-77
They changed to round shape (as in your picture)
From what I'm reading, all the 10 main rubber mounts for the body to the chassis are the same (for 77 and up). In another Parts Manual I'm reading 10.5mm (0.41" or ~7/16" for practical purposes).
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Earlier models
Please note that the manual states up to May-77 so there was an interval of time where both models were being produced!
http://www.carpartsmanual.com/nissan/pa ... /to-may-77
These are square shaped.
There are 2 of one thickness for the radiator grill body mount, and 8 of a different thickness for the rest of the main body mounts.
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In addition to these, additional flatter shims are under the tub.
Please send us the measurements of your body mounts.