They are the same as a given year of Canadian Chevelle, which is the same as the U.S. ones.

I know the telescopic mast & tip on my '67 is more of an oval cross section than the earlier design, and I believe the '66 is the same as the '67.

I think earlier ones (maybe 1965 or 1964 & earlier) used a different base cap than the U.S. Chevelles in that it was a black plastic base cap rather than a chromed base. No problem though if you had an earlier car, look for the same antenna cap as a solid axle Corvette (available reproduction FYI).

66 beaumont. I have had my original radio bluetoothed and refitted for fm as well.  I do not have an antenna nor a hole for one in my repop pass fender. Should I just install a repop 66 Chevelle antenna or can someone suggest another option? Thank you.

yep ,you are right Carl both my 66s had front and i moved to the back. Makes car look faster

I know there was a rear antenna option for Beaumont, so that would not be incorrect on your car.  I just can't say if it had to be power or if there was a manual rear antenna offered as well.

Good to know this. Thank you Carl.