GM T-3 headlights - New info

[jeffschevelle]

So that proves the mixing in of old style and new style bulbs, since my 07B Baltimore has new style bulbs and Bill's 07D Baltimore has old style bulbs

As noted above one of my Ribbed low beams is 62 7 2. The other Ribbed low beam is ?? 7 16 (has no month or line stamp). See pic below. But it is presumably June 16, 1967, since car is 07B.

Both Ribbed high-beams are 61 7 5. So production line 1, June 5, 1967. See pics below.

I texted with Bill, and his clear triangle high-beams are 61 7 5, and 63 7 5, and his clear triangle low beams are 61 7 5, and 6? 7 5 (line # not legible).

So, all that suggests that:

- Production line 2 changed over to Ribbed on or before June 2, 1967.

- Production line 1 changed over to Ribbed on EXACTLY June 5, 1967 (since we have both versions produced on the same date.

- Production line 3 changed over to Ribbed on or after June 5, 1967.

[67since67]

Apparently NCRS has recently picked up on this too! The latest version (7th Edition) of the Corvette Technical Information Manual and Judging Guide is revised that "Although typically clear, late cars may have vertical bars within the T-3 triangle". Thanks Jeff for the great info!!

[grantprix]

Great thread on this subject!

My "06D" Fremont Plant built '67 GTO has three of newer '68 style T-3's and one '67 style (left lower). I'm confident these are original to the car, but have not removed them to check any dates.

There is also this "06A" Pontiac Plant built 9800 mile '67 GTO time capsule with the exact same sealed beam configuration as my car.

[John Brown]

Whatever you do, don't wash those date codes with soap and water. Some (maybe all) of those stamps are water soluble and may dissapear with washing.

[mssl72]

Originally Posted by John Brown

Whatever you do, don't wash those date codes with soap and water. Some (maybe all) of those stamps are water soluble and may dissapear with washing.

YES!! What he said!