I was speaking with PST today, they kept insisting this kit had been used for 20 years by Wilwood with no problem..., and the reason it's not working for me is I don't have factory 15" SBP wheels with a 3" center hole. I then told him that those were never produced, SBP wheels have 2 1/4" center holes and even LBP wheels don't have a 3" center hole. I then added what you brought up, the studs being the wrong size for SBP wheels. This seemed to finally make it click with him that Wilwood was full of it saying this would work with SBP wheels. He said he would follow-up again with Wilwood engineering.