Second Generation Barracuda Year to Year Differences

For the 1967-1968-1969 Barracudas, post information on vehicle features that you know were different for that year. Include items that you know were one year only options. For the year to year changes, if you think the change was made to achieve a cost savings or to fix a reliability issue, note that if you can.
Lets not talk about the things that are common knowledge like: Idler Arm, Side Marker Lights, Rear Tail Lights and Front Grill, as well as the special built '68 Hemi Barracudas.
But other features that you know to be year to year changes, post them here.
Thanks