1970 Challenger R/T 3.23:1 OPEN is the STANDARD gear ratio & was not dependent on the engine

the OPTIONAL HEMI engine did not change or require any additional rear axle OPTIONS

the fender tag would not indicate if the subject HEMI R/T was 3.23 OPEN or 3.23 with the OPTIONAL Sure-Grip (~$42) - it would be noted on the window sticker and broadcast sheet