I just wanted to see if we can clear things up with the spacers. The parts book shows the 231 part number correct for the front and rear for Challengers in '70. 'Cudas got that up front too. That's the thinnest one.
The '71s and I believe newer got the 232s. That's the next step up in thickness and you can see the pic of that in this thread too. And lastly 'Cudas got the 870 extra thick ones for the rear. And also the springs definitely makes a difference in spacing for the rears. Without them the 'Cuda thick ones will fit on a Challenger rear.