help with axle ratios/axle

[rusty82]

been after a new axle for awhile now for the mk5 cortina. but been offered a nos axle the thing is it looks the same maybe abit more stronger looking but the diff raito is one i havent come across in the mk4/5 range cause its 3.77:1 any idea where this could be from or what name of axle it could be? all the mounting points are the same as my koln i ask this because

1.6 saloon is 3.89:1

1.6 saloon option and estate is 4.11:1

2.0 saloon and estate is 3.75:1

and the 2.3 is 3.44:1

so where did 3.77:1 come from? will it be any good in my mk5 1.6 type 9 until i manage to find myself a 2.3 axle for when i put the st170 engine in?