Why they did not use the flush sidelights for the entire production run never made sense to me , they had the molds , but in a cost cutting measure they decided to use a 1 part fits all cars side light unfortunatly .
Between the 70 & 71-74 models almost every part was modified in some way , everything from window felts , seatbelts , mirrors , console , gauges , it is a very long list !!
The 73-74 car became much heavier , my 70 440 Chall R/T SE weighed 3550 lbs , my 74 340 Chall weighed 3780 After I had removed all the extra bumper re-inforcement pieces & moved the bumpers in flush . at least disc brakes became std !