the BK bones mensioned in Ryans setup from the worlds are/were a prototype.
Don't quote me on this but I seem to remember them being a CVD still bit they used bearing rollers at the bone/outdrive end.
Its been nearly 2 years since I seen these so I could be wrong
in the UK we have been running the BK2 rear wishbones/Trinity BK2 rear hubs since the BK2 came out.
works very well
EDIT - just noticed you used the short rear arms with the BK2 rear end...? what is the point, that is the same as standard