[grahamp]

Old pinion head - here are some answers. Yes, my 1969 Judge came out of the factory with a 3.55 Safety Track HD rear axle and I would like to go back there with a correct date code if possible. Car was build at Fremont in April 69
Here are the stamps on the McKinnon 12 bolt Chevelle rear end - casting number is 3959038, the assembly date is 0325K and the date code is C249. I could not find a ratio code. I now doubt this is a posi unit, will try and do the wheel rotation test later today. The axle does have a GTO posi sticker XH which fooledme for a long time! I believe the McKinnon unit has a higher ratio than 3.55, much closer to around 4.00. The Judge is in Vero Beach Florida. It is a 2- Car, looks brand new and has won many awards. The axle imposter is a shocker so I want to fix it and get as close as possible to the original. Engine is original, 4 speed Muncie has just been rebuilt and has the correct casting and date code numbers. Thanks for any assistance . Chevelle unit looks as new.