The Proforged lower control arm pivot shafts will work with the factory k-frame but not the QA1 k-frame. The design is just different enough on both to prevent the shaft from seating all the way in. The QA1 uses 2 welded in bushings, a larger and smaller diameter to accept the taper on the pivot shaft and it works fine with the stock pivot shafts but the Proforged shaft has the first taper near the threads much closer to the threads and not as gradual as the stock shaft. The smaller bushing on the QA1 k-frame offers a hard edge where the bushing begins and will not allow the shaft to pass. I should have left my stock pivot shafts alone. I cant blame one or the other, they are just both different and will not work together.