Castlemaine rod shop have a conversion where you use your existing stub axle, fit a later falcon disc rotor and girling (Holden) calipers. This is quite a good conversion as it does not effect steering geometry like some other conversions.
here is what they list is as and the link
DB 23 Ford vent discs to XK-XP Falcons, Compact Fairlane (drum brake stubs)
http://www.rodshop.com.au/chassis.htm