Commodore Brake Wheel Track Increase?

Not sure if this helps, but is similar to what you are after. I have an EK wagon with HR front end, HR stub axles modified by CRS to take Commodore bearings, VN/VP brakes (with CRS adaptors) and run 26P-offset Commodore wheels.

HR Holdens originally had 6mm positive offset. The proposed wheels have 20mm more offset than the original assembly, in the positive direction (less axle load). The proposed 178mm (7”) wheels however are wider than the standard wheels fitted to the vehicle as original equipment (5¾”).

The Castlemaine Rod Shop indicates that the modified stub axles have been designed for a maximum track of 1455mm. The proposed vehicle track (ie the combination of CRS, HR and VP bits) is 1436mm (when measured as per the Castlemaine Rod Shop to the centre of the tyre). The original HR track was 1369mm, so my track has increased 67mm.

Most State's rules allow for a 25mm track increase, though normally note that this is based on the specifications of the axle components used. Because my stub axles were engineered by CRS for a maximum track of 1455mm, my certifying engineer was happy that I was still within the specifications of the axle components used (i.e. he was comfortable using the CRS specifications on their product, rather than the original HR Holden specifications).

Caveat emptor - many certifying engineers will use the HR specifications, so it pays to have this conversation up front. In your case, the engineer may get cute and either use HR track (1369mm) or HT track (1476mm) as you have mixed-and-matched suspension components.

Cheers,
Harv