Outer Limits 4x4 Board

Howdy.
I've got a set of 60 diffs sprung over under a 40, and i'm looking at buying a 1995 75 ute - i'm hearing that the 70s and 40s spring perches are the same (or almost the same) distance apart??
Does anyone have (or please measure) the distance between the leaf spring measurement for a 75??
Cheers
Rob

The perches on the 40 diffs are further inwards on each side compared to the 70 set up.

Do you know by how much??