Did not realize 3 speeds were avail. in E bodies..............

I believe they also put 7 1/4 rears in some in 1970 only. I think the slants were 70 only.
I had a 71 Challenger that was a loaded 318 car. It had a 7 1/4 rearend in it from the factory. I jerked that thing outta there so fast it would make your head swim....lol. Swapped in an 8 3/4 and a 727 at the same time.