That rounded upper CA looks like it would work with an air bag system, maybe they changed for that reason so they wouldn't have to build two different arms?
73 rebuild Did u use a 4l80e trans? Mine had to be cut just to set the motor in place not to mention the angle the trans tail housing has to be to get the right pinion angle
no tunnel cutting for my...5.3 700R4 install in my '73. I knotched the oil pan so the motor could sit lower.