Having been somewhat alarmed by the configuration of the rear suspension as depicted heretofore in this thread, I inspected and conversed with Steve Watt regarding it.
First of all, the “wishbone” configuration bears no relationship whatsoever to that proposed for the Bloodhound, which is basically a conventional double A-arm suspension with pullrods--similar to most open wheel race cars.
Secondly, the 1.75” “track bar” is, in fact, a 1.75” anti-roll bar, which is mounted in the large, bronze bushed holes gusseted into the frame above the axle. This item is the primary method of resisting the axle input shaft torque. Although not shown in the above photos, Steve says it will be in place when in use--which is a good thing, since the wishbone single Heim joints, loaded in bending, are likely not up to the job without it.
The intended function of the upper and lower “wishbones” is to provide lateral location of the axle. However, as configured they will also share, to some degree, the anti-roll function, which is worrisome.