Original 67 4 Way 552 and Turn 323 Flashers - 1381303 round & 3836338 square

[big iron]

I am looking for information on 67 year flashers as 68 and 69 had different flashers.
Have done searches here and on TC but very, very little info. on flashers.
When did the DOT script first start on the flashers?
Who were the major suppliers? I found Tung Sol and Wagner (?) but Tung Sol seems to be the most widely used.
Most widely used flasher is the round rather than the square type.
What was the reason for optional flashers? Was the RS option Z22 one of the reasons?
Anyone have pictures of original flashers?
Thanks,
Bob

[His67PC]

Here is a harness I removed from a parts car in the late 70s or early 80s.  Signal-Stat 175 and 144 installed.

[His67PC]

Here is another harness I removed from a parts car in the late 70s or early 80s.  Also had Signal-Stat 175 and 144 installed.

[His67PC]

This harness is from a car I have owned since 1977.  It is an 04A built Norwood car Signal-Stat 170 and Tung Sol 552 installed.

[His67PC]

Another interesting tidbit, the Signal-Stat 170 and 175 have a number stamped into the side.  The 144s do not.  The picture below is the 170 unit with an S 406.  I thought these might be date codes (the 175s are S 127 and S 247) but knowing the build date of the harness with the 170 and having 406 doesn't make sense for a build date.

[big iron]

His67PC,
Thanks for the reply. Your picture of the silver 552 Tung Sol flasher is interesting.
I have decided to narrow my search to the Tung Sol 552 flasher that may have been used in my 67.
I will start the list with your silver 552 TS flasher.

Silver 552 SAE J945 Pat RE 24023
Gold    "     "     "         "          "                Long Island Corvette
Silver 552 DOT       Pat 3218415      eBay
Gold    "     "               "          "                  One I have and also seen on eBay

Now some history.
Congress establishes DOT Oct 15 1966.
DOT starts operation Apr 1 1967.

Any one venture a guess as to which flasher could be used in an 05E build 67 ?