@64Dart Disagree... just did this on my '67 and the holes are there in non headrest seats. If you get '67 headrests (1 year only) you can buy the install kit from Classic Ind.Seat backs the frames are different for the headrests. Same with Barracuda.
Just had a set apart for Todds 67. We wanted to install the headrests into the existing seats . Couldn't do it the frames needed to be changed
I had installed headrests in my '67's seatbacks, but it wasn't a great (the way it was done didn't have great support). Eventually I had ABC redo it using a 70 split bench seat back frames modified. The laer seat had latches for the seatbacks. That was the main reason I recall we scavenged the 70 seat frame.Seat backs the frames are different for the headrests. Same with Barracuda.
Just had a set apart for Todds 67. We wanted to install the headrests into the existing seats . Couldn't do it the frames needed to be changed