Jim need to study and think about these but thought I might suggest that you put something in the future pictures to illustrate size for comparison. Possibly something as simple as a quarter rather than spend the time measuring or something like that.
Yes, you can teach an old dog new tricks. Let's see if this tip is picked up by others.
Pic 4 - the modulator line bracket. From the picture, it's a 66 and 67 C4 V8 application. It's not on my 65.
The first clip holds the modulator line at the passenger side top bell housing bolt.
From Jeff's picture, it appears to be on the driver's side, and son-of-a-gun (I just walked out to my garage), there's one on the drivers side of my 66 HP.
Pic 5 - a second modulator line bracket.
Pic 6 and 7 - the mystery bracket, with the "stressed" bends indicated by red arrows.
At this stage of research, I'm going to straighten the bend neared the mounting hole, for a different perspective.
Jim