Says its a rare 4:27:1 Sierra diff? Never heard of this one

It certainly looks like a Sierra LSD but not aware of that ratio. Maybe he got confused with the tags?

If I remember right its a 7 1/2" diff. Don't know if they were LSD or open with bolt on shafts. Hope this helps

Kev....

there are a lot of rare funny ratios out there, esp in rally circle.

Could it be a Granada Diff?.

All the Sierra's were 7", except the Cosworth which were 7.5".

All the Granny Diffs were 7.5"

Well at least I think thats right. It would explain the odd Ratio.
Check for Granada Ratios.
Not sure if this was fitted to the Scorpios as well. (Dont know when the change to Front Wheel Drive occurred)

Definitely was a 4.27 but more rare than a 3.14.
You would need a very close ratio gearbox and a high revving engine to make it work

yes there definately is a 7.5 inch diff 4.27 ratio it is very rare,
i have one, it is fitted with the flanges for disc brake bolt on shafts, if anyone is interested?
i have 3.36 ratio too...