PS section starts on page 576.
I see three seals listed in 1970 Challenger manual and looks the same in 1973 parts catalog.
If you look at the photo and identify which part, can get other numbers if needed.
19-19-35 seal steering gear worm shaft 2948 859
oil seal steering gear shaft 2267 129
19-19-70 seal steering gear worm sleeve 1822 324
19-01-52 seal steering gear reaction upper 1822 151
o ring steering gear reaction lower 1822 149