The only difference I was told is the top collar section. The ones from 70-71 did not have the key releace lever on top. From 1972 and up there is a key release lever to top of the collar. My top collar section(s) have the key release lever, so I am going to go with the newer ignition lock set. The ones I've seen are around $26. Does NAPA etc carry these or do you have to get them from a Mopar vendor?