Snaken I too am having 3.73:1 in my borg, but I'm buying new crown & pinion from WA Diff Centre in Perth, they quoted me $595 fitted, aparently there are no aftermarket 3.73's you can only buy the genuine gears. I'm putting a new LSD 4 pinion 28 spline centre in it too, $650 fitted.
I've heard that people have swapped borg & skyline gears too, not too sure about the salisbury diff though?
Firebird & Camero came out factory with 3.73's from around 1988 to 1991, is this any help? if you find a good second hand set ask if they have another set for me
If other people have more to add to this thread I'd be interested too
Simmo