1963 hood prop bolt head markings

[Richard G.]

I am attempting confirm some of the hood prop bolts on my December 1963 Coupe.
It is my understanding all should be zinc plated
Top hood bolts labeled (21) 9409107.
Bottom fender bolts labeled (23) 3797168.

To avoid confusion, I am only writing about the two bottom fender bolts labeled (23) 3797168 in the assemble manual.


Pictured below is the bolt I believe is original next to the Paragon reproduction.
The black bolt is one from my 63.
Both are the same length and have the captured washer. Honestly they might be better than average reproductions.



Here is where we get to the tough part;
The manual says "special bolt that has a 3/8 head" head with a headmark depicting an anchor and a large "T" which splits the lower half of the bolt."

Possible I mismanaged my original bolts and they came from somewhere else? Or something is incorrect because the after-maket bolt fits the description better than my original? My JM is from 1994, I failed to find my newest JG so it is highly likely this has been addressed. Thought I would throw it out here anyway. I do need to re-plate my hood prop bolts in any case.
Rick

[Alan D.]

Re: 1963 hood prop bolt head markings

Comments are from a Mar64 car:
bolts are bright (zinc) and should have the "T"
The repo anchor is not perfect. Have attached a typical bolt,
however not the specific one (may get a photo later)
Now since you have one of those 63, changes were occurring ALL the time.

So the dark bolt with no "T" maybe correct but not expected to be seen during judging.
I have always felt that if what was original is not called in the JG and it's a simple change
(such as replacement of bolt) go with the JG until the JG catches up with reality. If it's a major
change then keep original and take the point reduction, but point out to judge it's original - do not argue.

The anchor can face in either direction, towards "T" or 180 degrees away from "T"

[Edward J.]

Re: 1963 hood prop bolt head markings

Rich, I am sure the bolts were anchor heads and 3/8 head, bottoms were black phosphate and the top were Zinc. and 3/8 head size also. I believe that the anchor heads had the T but my car is home on lift with a car park under it. I really think that the zinc bolts will work for uppers and lowers, but my 63 had two different finishes.

[Don H.]

Re: 1963 hood prop bolt head markings

Here is one of my lowers on Jan 64 coupe. I inverted the shot to better show the anchor. Quite certain this is original to the car. The other lower is the same, but is rust colored and under the harness loom. The uppers are the same headmark, but appear to be black phosphate/rust finish. The anchor bisects the top of the Tee.

[Timothy B.]

Re: 1963 hood prop bolt head markings

I believe that lower pointed bolt is the same as the bolt that attaches the dash to the birdcage so check for the headmark on those bolts before you install any reproduction bolt.

The upper bolt is the same as the bolt that secures the speedometer gear retainer to the transmission rear extension.

[Louis R.]

Re: 1963 hood prop bolt head markings

I am trying to identify the proper bolt for attaching the prop to hood. My car has anchor head markings but when judged next to another 1963, I was tilt the attached “U” head marking was correct....I’ve also seen reference in my searching to an “E” marking?


B076B9AA-56DD-4457-9CEA-4F3D9369713B.jpg

[Mike E.]

Re: 1963 hood prop bolt head markings

I, personally, would use the original that you took off. Sometimes we try to be too prescriptive about a specific bolt when the factory and the manufacturer were not quite as motivated as we are.
Attached is a picture of four 1970 L46 valve cover bolts that came off the same cover. The car is a low mile car, parked in 1980, by the original owner who had no interest in bolt head markings, or any other originality. Fortunately, the tabs on the differential cover broke before he put a lot of miles on it and turned it over to mechanics.
Check out the 4 "M" bolts, again from the same valve cover:
valve cover bolts.jpg

[Louis R.]

[Frank D.]

Re: 1963 hood prop bolt head markings

The point was to illustrate that there were anomalies in other hardware components, so that variances weren't uncommon. I don't know how "judged next to another 63" is relevant. The judging is against an objective standard - the Judging Guide...

The latest 63/64 Judging Guide states that the hood underside prop rod bolts are hex head with the anchor symbol and two perpendicular lines (the "T" mentioned above)...that is what my May 63 car has... There is no mention of an "E" or "U" headmark.

Not much mystery about what is written. Can there be factory deviations ? I never say "never" with 63 cars.

[Peter H.]

Re: 1963 hood prop bolt head markings

I Was The Buyer For A Medium Size New Car Dealership And In The Last Five Years The Hardware Bolts + Nuts Were Marked With That U Mark.
They Were Packaged In Bags Marked Made In China ! Go Figure Hamilton Ontario Is A Steel City .Off Shore Hardware was Cheaper .
Peter H.

[Louis R.]

[Frank D.]

Re: 1963 hood prop bolt head markings

Frank, thanks for the reply and I have the judging manual...was just trying to make sure I didn’t miss something. The manual is clear, anchor bolts at all four locations with bisecting lines. The car being judged next to me had the “U” bolts above and was “deemed” correct versus mine ...with anchors. I believe it was just a miss now by the judges...no one is perfect and they do try very hard to be fair and correct!

Yup, sounds like the judges got crossed up a bit...it happens.

[Alan D.]

Re: 1963 hood prop bolt head markings

Did get some time to look over the subject area. The results are from a Mar64 car.
Now to add a little more confusion. There are 3 different screws for the hood support,
#21 (9409107) – the upper support to hood, not being discussed *listed as 1/4-20 x 5/8
#23 (3797168) - the upper bracket to fire wall, being discussed *listed as 1/4-20 x 7/8
#24 (3797079) – the lower bracket to fire wall, not id in discussion * "


Note on #21, if a longer screw is used here it may cause a crack in the hood (careful)


I found that #21 & # 23 are about 0.7 “ long while #24 (lower) is about 0.8 long


Now the AIM has 3 different part numbers listed however my car seems to have only two different screw assemblies. The only different in the three seem to be in the length. My hood support has been removed many times over the past 53 years, but always the original screws were used again.

It is tough to distinguish a 21, 23, or 24 from each and on the factory floor bet workers just garbed a

hand full of screws and installed. Know I would just grab the shorter screws (#21) and use them.

One interesting thing found was that the bracket asm (3797473) held in place by rivet (3828548) had no blackout or undercoating behind it thus confirming it was attached before that step.
Have not been able to find any specs for 21, 23, or 24.

[Michael G.]

Re: 1963 hood prop bolt head markings

I've gone over this few times before here, but one more probably won't hurt:

Virtually all fasteners in GM plants were double or triple sourced, meaning two or three different manufacturers. Such fasteners were shipped to GM plants in cartons of say 2500 pieces, on a pallet with many cartons. All cartons were then stored in a central location, by part number, at each plant. It was not unusual for the same part to be present in that plant's central location from two or three manufacturers.

The hilo driver who supplied these fasteners to the line cared not what the supplier name on the box was, only that the part number was correct. So the driver would deliver the boxes to the line and leave. Line operators at a job site usually had some container at their site for each fastener they installed and they would refill this container frequently, pouring them from the box of fasteners that had been brought to them by a hilo driver.

The operator almost always poured some parts into his container when it became low, mixing the "old" fasteners in the container with the "new" ones, resulting in the container possible containing parts with two (or three) different head markings. The operator took them out as they came to hand, never glancing at the head marking. Nobody cared.

It is therefore possible, even common, that a component might be attached with two or three of the same fasteners, all of which have different head markings. If a fastener found on a car is of the correct construction, with a known GM supplier's head marking, and the judge recognizes the head marking as being from a common GM fastener supplier, there should be no deduct.

More critically, subtle differences in head markings were ALWAYS present on fasteners, as the logo was cut into the heading tooling by a tool marker with no instruction to be exact, only to apply something close. These heading tools were changed frequently, during a manufacturing run, each logo slightly different than the last. It was not important to anyone.

Let's quit being so anal about this, no one in those days cared, so long as the car got out the door.

[Timothy B.]

Re: 1963 hood prop bolt head markings

1963 AIM section 11-13 sheet 11.00

Part #21, (9409107) screw & L/W ASM hood support to hood is also shown on sect 12 B 1.00 it's 5/8" length indented head.

Part #23 (3797168) bolt & L/W ASM, hood support to inner fender is also shown sect 1 A 23.00 dash to bird cage, it's indented head pointed tip.

Part #24 (3797079) support ASM