From the two types of column I have here:
a) FB/EK Holdens are 5/8-36
b) LH Toranas are 11/16-36
Note that sometimes two vehicles will have the same splines, but the steering wheels will not interchange because the blinker cancelling mechanisms are different. A good guide to what will interchange is the SAAS boss kit listing, attached below.
If you need to get splines repaired or recut, it looks like this mob can do them:
http://speedex.com.au/index.php?route=p ... y&path=138
The adaptors shown in the link above would be a nice option too (sadly for me, LH Torana columns are bigger than FB/EK steering wheels, so I cannot adapt an original wheel onto my wagon project

Cheers,
Harv