I know somebody with an 87’ series 3 (6 cylinder) that needs a diff. Do you know the gear ratio?

 

Sorry I don't. But it I would be hard pressed to believe there were options for the v12.

There is a picture that shows numbers on the housing

 

Ratio would be 288

 

I have a complete 86 IRS from an XJ6 but the shipping may be prohibitive.

 

I have the capacity to palletize and prepare for shipping no cost but shipping is at buyers expense.

 

the xjs dana unit is a 2.87:1 powerlock(lsd).

the non-dana is a 2.88:1.

hardly a difference though

 

I believe the series III XJ6 Differential is either 331 or 354 and the diff. is open. Only the VDP was a power lock.
The "other" XJ-S diff. would be a Salisbury and is recognized having a drain plug. The Dana does not have a drain plug.
I do have a 1986 XJ6 complete IRS in stock at one of my storage garages. Shipping would be from Pittsburgh, PA and I can palletize the unit.

 

This unit is obviously marked as a dana

 

It can be replaced by the Salisbury unit.