Did the Camaro and Firebird use the same axle codes on the axle tube? I have an '85 IROC that was originally an automatic with a 3.23 Posi and was converted to a T-5 and 3.73 gears. I have been trying to ID the axle and can't find the number in the 1985 Helm or the 1982-1992 Haynes. The number stamped on the axle tube is "9P D C150 2". Any ideas what this axle came out of?

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1985 Yellow IROC-Z 5.0 HO, T-5 3.73 Torsen, 4 wheel disks
PFCM pads, GTA wheels, Koni yellows, B&M Ripper, Dynomax