Steel bolt for the connecting rod blade on 1923 – 1927 Cadillac V8. For use on “inside rod”. Cadillac part number 58128, group 8.2090. Two required per rod, eight total per car. Material: 4140, Heat treat grade 8 Finish: Natural Thread: 3/8-20 Thread length: .840 OAL: 2.840 Length under head: 2.590 Head OD: .625