Hy wickedinhere, welcome, My maintenance manual does not tell me the center hole dimension, however it does give me the bolt circle and stud count of the Kelsey wheels that a 1967 C50 Chevrolet came equipped with, that information is ten studs on an 8.75" bolt circle. Note 8.75" bolt circle rather than the 8.25" bolt circle in your question, hope that helps.