Original Details

[cericd]

Before I purchased my truck I had some definite ideas for how I wanted it to turn out, 4"/6" drop, vintage mag wheels, etc. but once I had the truck for a while my taste in styling began to lean more toward bone stock or factory optioned trucks.

I assume I'll have multiple questions regarding factory correct details so, I've started this thread in hopes that it will keep all this info in one spot for anyone else who might have the same questions.

[cericd]

My first question is about the screws on the factory mirror arms of my 1970 C/10. My truck has had one exterior repaint to the factory, Medium Gold, color. The mirror arm screws appear to be original but were painted over. According to my research, I believe they were originally unpainted and silver in color. Does anyone know for sure what the original finish was? Here's a pic of my screws for reference.

I realize these screws are reproduced, sort of. The heads are slightly different. I'd prefer to replate the originals or find some nice or NOS ones. Anyone know the part number for these?

[cericd]

I'm also curious of the acorn nut used to attach the mirror head. What would the original finish have been? Mine have been painted over.

[pjmoreland]

I don't know how the mirror arm screws were finished originally, but Classic Parts sells a decent reproduction of them. It's part number 58-413. I used them on my truck to replace the missing passenger side mirror, and they look like the originals to me.

https://www.classicparts.com/1956-69...info/58%2D413/

[cericd]

Thanks pjmoreland. I have a set of the reproductions. Can't remember if I got them from classic parts but I remember noticing the difference in the shape of the heads compared to my originals. I thought the repops were stainless but I might have been thinking of the repop door panel screws.

I'd still like to know what the finish was on the original mirror screws and the acorn nuts. Also, if anyone knows the GM part number for the original mirror screws.

[cericd]

Here are the pics that I found that lead me to believe that the screws were originally unpainted.

[Accelo]

Here is a picture from the GM historical site.
Not very clear but sure looks like they were unpainted to me.
Most of the picture were with the optional mirrors.
Of course they are up selling.

[tutone]

My guess would be unpainted screws as well. When they were sent down the assmbly line, the white top and A pillar was shot without masking that area so it received an ample amount of overspray. Body color was next and the white top was masked off. The doors were painted pretty much the same way. Doors were most likley mounted and aligned and sent down the line. If the mirrors like your truck was optioned with, were ordered, it would make no sense to paint the screw heads, only to scratch them up during install. The installer would grab the correct color mirrors and drill the proper holes and slap them on. Probably in less than 45 seconds. I spend a lot of time watching assembly line videos. Maybe one exists for our trucks. All this is opinion, based on stripping , sanding and peeling back the layers of time. I watched the building of the new Dodge Challengers the other day and it was 80 percent automated. The engines received the most human treatment of all.

[cericd]

Here's the difference between the originals and the reproductions. The head of the reproduction screw have a thick edge around the head that causes the to seat a bit differently than the originals. Also, it appears that the Phillips slot in the screw is a bit larger on the reproductions. Is it likely that the originals were clear zinc coated from the factory?

[Keith Seymore]

Originally Posted by tutone

My guess would be unpainted screws as well. When they were sent down the assmbly line, the white top and A pillar was shot without masking that area so it received an ample amount of overspray. Body color was next and the white top was masked off. The doors were painted pretty much the same way. Doors were most likley mounted and aligned and sent down the line. If the mirrors like your truck was optioned with, were ordered, it would make no sense to paint the screw heads, only to scratch them up during install. The installer would grab the correct color mirrors and drill the proper holes and slap them on. Probably in less than 45 seconds. I spend a lot of time watching assembly line videos. Maybe one exists for our trucks. All this is opinion, based on stripping , sanding and peeling back the layers of time. I watched the building of the new Dodge Challengers the other day and it was 80 percent automated. The engines received the most human treatment of all.

Trucks were painted with doors on; no drilling in the paint shop. All drilling would already be accomplished in the body shop.

K

[factorystock]

Originally Posted by tutone

My guess would be unpainted screws as well. The installer would grab the correct color mirrors and drill the proper holes and slap them on.

I agree on the unpainted screws, unless some assembly plants mounted the standard mirror brackets before painting. Factory primer under mirror bracket plate would prove this. The screws and cap nuts for mirrors were originally coated with zinc or something, but coating would eventually wear off and start to rust. But where did the installer find the correct color mirror brackets? Dangling on some hooks with the cab when painted? Sitting on a shelf somewhere? Hmm. Interesting.

[72c20customcamper]

I would think the bracket was attached to the door and painted with the door then the head would be installed as it went down the line .

[tutone]

Like I said, I havent seen an actual assembly line of 67-72s. Makes sense on the doors already being on the truck. My 71 has org paint under both mirrors. Stained from the gasket of course. Also, it being chrome forced them to put it on after the fact.

[Accelo]

When I purchase gaskets for my mirrors I found two different types.
one was cut flat and the other had a rubber ridge around it.
Unsure which is stock but I liked the ones with the ridges and used them.

[cericd]

The ones without the ridge would be closest to stock.

[Keith Seymore]

(subscribed)

[factorystock]

Brand new '69. Argent silver mirror head with unpainted bracket screws. Same for '70. Sacramento dealership, Fremont assembly plant. Even on a brand new truck, moldings could have been better spaced and aligned. As others have rightly mentioned in the automotive hobby, GM was not in the business of building show vehicles, they didn't have to, they probably had 33% of the market in these days.

[cericd]

I agree that logistically, mounting the mirror arm to the door prior to the door being painted makes the most sense but then you would end up with no body color on the door behind the mirror arm. Also you would likely have body color overspray on the mirror arm gasket. Since my truck has had one exterior (original color) repaint, my truck doesn't work as an example of "factory correct" in this instance.

EDIT: Looks like factorystock came up with a great "evidence" picture as I was composing this post. (see post above)

I already posted a couple pics in this thread that lean toward unpainted mirror mount screws. Also, Accelo posted one from the GM heritage website showing unpainted screws. Here are a couple more from the 1968 and 1970 truck brochures. I realize that the images in these brochures were not always 100 percent correct, but it's further evidence none the less.

[Already Gone]

The pic is fromnan original paint 70 GMC I had a few years ago and u can see the screws are not painted.

[cericd]

Also, here are several pics, gathered from the forum and ebay, of takeoff mirrors showing body color paint on the backside of the mirror mount which would mean they must have been painted prior to installation.

[cericd]

Thanks for the confirmation pics factorystock and Already Gone.

[factorystock]

Originally Posted by cericd

I realize that the images in these brochures were not always 100 percent correct, but it's further evidence none the less.

I agree, many photos, especially in the '69 brochures are doctored. Some are actually '68's with touched up grilles.

[kev2809]

if your not using your spid or don't have one, try to find an old brochure. they usually show how they rolled off the lot. not very detailed though

[cericd]

Originally Posted by factorystock

I agree, many photos, especially in the '69 brochures are doctored. Some are actually '68's with touched up grilles.

My favorite are the odd hubcaps in the 1970 brochure where the black "gear" markings wrap around the edges of the hubcaps. I'm glad they didn't go into production like that. Kinda looks like a basketball from head on.

[cericd]

New Question: Does anyone know the correct size acorn nut used to attach the original round side view mirrors on a 1970 C/10. Ideally I'd like it to have the same pointed crown and be finished in clear zinc like the originals. Also, what size/type washer would have been used originally? Mine are missing. Lock washer maybe? My copy of the parts catalog doesn't list the part numbers or descriptions of the fasteners.

Here are a few pics of what I'm talking about.