Here is the dump off of a 2006 VZ Commodore, Single Screen, Manual Vehicle,
LVL1 Standard,
0x03C - 0x03D looks to be speed calibration in imp/km, while the speed displayed looked to be 6120 imp/km, I would not put it past Holden to scale the displayed speed down a little, rather than display the 6232 imp/km i read from the eeprom
for anyone bench testing there cluster, divide the imp/km by 60 and that will be the Hz to drive into the speed input to display 60KMph