I just picked up this '70 4-door yesterday, and was thrilled to find the olds 12-bolt cover posi rear end. What would have been the factory ratio, behind a 350/350 4-barrel?

Also, has anyone ever seen the R2 code stamped on the back of the passenger axle tube, but the rear being a posi unit with a different ratio than 2.56 open?

Steve

 

Steve,
Not sure about the code, but I know that if the car had AC, the highest(numerically) ratio they would install was a 3:23. I've heard that was to keep the ac compressor from spinning to fast for to long a time, or something similar. Congrats on the find!
Scott

 

Thanks, Scott.
Nice to hear from you, have a great holiday.
Steve

 

If it is a R2, then that was the factory gear, non posi, but after 40 years, who knows?