The BBM was originally owned by Dud Dansie and named for Bakewill Bridge Motors. It is most famous for having a rotary valve headed Holden (grey) motor. By the time Jim Doig bought it was fitted with an more normal headed Holden motor. It also had an Armstrong Sidley pre-selector gearbox. Rear end was double wishbones with differential based on a Holden. Front suspension was Holden (FC/FE?).
The following photo shows flag marshals in a typically dangerous situation (especially with the BBM there!).
On the grid at Hume Weir. Sulman Singer ? (52), Citroen Special (Bob Winley) on right of front row. BBM in foreground.
I think the following close up may have been a bit earlier – note the separate exhaust pipes.