GM T-3 headlights - New info

[jeffschevelle]

I have always read that the T-3's with the clear triangle (4-bulb system) were used through the end of 67 production, and that the ones with the ribs in the triangle were first used on 68 model year cars and are incorrect for any 67 model year vehicle. (And that's what the 67 NCRS judging manual also says.)

Well, I have proof now that that is not correct. Attached are pictures of an original Ribbed T-3 bulb with date code June 2, 1967 on the back. Date code info copied from the Camaro forum also attached, which shows the stamp decodes as:

62 = June, production line # 2
7 = 1967
2 = 2nd day of month

This is one of the 4 original Ribbed T-3 bulbs in place on the 67 L78 Chevelle survivor that I recently acquired (discussed here: https://www.yenko.net/forum/showthrea...=jeffschevelle )

The car is a late build with 07B trim tag date, so the bulb date is appropriate for the car.

When I got the car I thought it was odd that all 4 of the headlights were Ribbed T-3s on a low mileage car, which would have meant that ALL FOUR headlights got replaced sometime between 68 and 71. So I removed one to check the date, and there it is -- June 2, 1967!!

I will remove the other 3 and check them later to see if any are dated any earlier than this one is. But for now we know that Ribbed T-3's were in the supply pipeline at least by June 2, 1967. Of course there could have been (and probably were) clear triangle bulbs still in inventory and being used in the assembly plants after that date along with the newer ribbed bulbs.

But with this info, NCRS and MCACN judging criteria needs to be updated to allow EITHER version to get full points on a 67 built in June or July of 1967. I am not a member of NCRS, could one of you who is a member post a link to this thread in their judging forum?

Now I have to go buy an NOS set of ribbed bulbs for the L78 elcamino (07D trim tag) we're restoring!! I had 5 sets of NOS ribbed bulbs and sold them all because I believed everyone who said they were not right for ANY 67 !!!!!!!!!