It appears that in about May 1966, St. Louis built cars switched over to the '67 method for securing the front brake crossover line to the frame crossmember. The '67 method uses 2 flat clamps (bolted in a hole above each of the nut plates used to mount the lower control arm) where the '66 method uses a single wire clip (in a hole in the center of the crossmember). Perhaps St. Louis ran out of either '66 style clips or crossmembers late in the '66 production run(?).

My June 15, 1966 car uses the 2 flat clamp '67 method and has all 3 holes. I know of 2 May built cars that also use the '67 method.

A favor please: If you have a late '66 (April or later) and are (reasonably) sure your front brake line is mounted the way it was originally, I'd appreciate hearing from you!

The information that would be useful:

VIN Number (e.g. 194676S124431)
Build Date (e.g. June 15, 1966)
Style of Hold Down Clamp (2 Flat or Spring Style)
Number of Mounting Holes in Crossmember (1, 2, or 3)
St. Louis Car (yes or no)

Thanks in advance. I'll post the results after I tally the responses,
Tim Ehlers