What is the difference between 66 and 67 dashes plain or a/c dashes. If it is the opening where the steering column goes how do you know which one is for a 66 or 67? thanks

66s have a smaller opening for the column. the easiest way i have found on Malibu or SS dashes is how the panel above the glove box attaches. 66 the trim (2 pieces) was screwed around the outside edge, where as 67 the trim was one piece with 4 screws in the center. I believe the bracket behind the column hole is different too (and won't bolt in)

66 headlight and wiper switches are closer together than a 67's also so the dash strip won't interchange.