Yes, I have your BAC Coupler PDF instructions. They do NOT specify where the set screw should be positioned on the input shaft. I assume that the screw should make contact with the input shaft in the middle of the "valley" between the two splined portions of the shaft. Is this correct? If I position the screw in the middle of this valley, the splined part of the shaft closest to the gearbox just barely engages the coupler. On the Stock box input shaft, the Stock coupler engages the splined part closest to box at least halfway (halfway engaging the splined surface). The engagement of the splined part closest to Borgeson box with the Bergman coupler (if set screw is in middle of valley) is significantly less. The last photo shows the coupler position with the set screw right in the middle of the valley between splined portions of input shaft. So I'm confirming if I am doing this right or wrong.