Looks like there is a dually rear wheel option for Transit. Rear discs definitely 280 mm diameter, solid, thickness and hub match ours, but they appear to be 108 mm 5 bolt circle, not 4 bolts. Stop tech has sport versions with grooves etc. Maybe Sico just had a batch run with 4 bolts. Considering a FoMoCo set of brackets, rotors and dust plates might run under $200, an extra $300 for 4 bolt rather than 5 seems a little high.