I've only recently purchased all the parts required to convert my VZ 1 Tonner to the larger front brake caliper/rotor setup
What I found while researching this upgrade was that the following models all had 320mm front rotors and the larger PBR calipers from the factory.
# VZ SS Thunder ute
# VZ SSZ Thunder ute
# VZ SSZ Sedan,
# VZ SSZ Crewman
# 2005/2006 VZ Monaro.......Pontiac GTO in the USA
These larger VZ calipers are commonly referred to as C6 Calipers, as they are the same calipers that were fitted to the C6 Corvette
As per the below pics, the larger calipers have different (offset) mounting hole configurations compared to the standard calipers
Caliper to suit the 320mm rotor......Bolt holes offset to each other
These calipers use a DB7599 brake pad
View attachment 212151
Caliper to suit the standard 296mm rotor......Bolt holes in line with each other
These calipers use the DB1331 pad size
View attachment 212153