1967 Bolt head ID and application

[Garry B.]

I recently bought a two owner, 46K mile '67 and have been assessing the overall originality of the car. The prior owner made some small but non-original changes that I have found so far, but in looking at the bolt heads I am scratching my head. I have found many bolt head M, L, TR and others in the right places, but this one has stumped me. I have found these bolt heads with triangles in many places that should have had not reason to be replaced such as the female hood latch to firewall and this one that attaches the hood support arm to the inner fender. Before I assume they are not original, can anyone tell me if they have ever seen these used? My car was built on February 1, 1967. Thanks for any insight you can provide.

[Leif A.]

Re: 1967 Bolt head ID and application

Garry,
I can't speak to the bolts (originality) but the hinges and bolts were in place during blackout and, therefore, should be black. Wonder if the latches have been replaced for some reason?

[Garry B.]

Re: 1967 Bolt head ID and application

Leif, as always, thanks for your response. Although this photo is of the lower hood support mount, I understand what you are saying about the black out. From my experience though and as i understand it, the black out process and application what relatively sparse and with the cadmium plating the paint didn't remain on these parts too long. I obviously didn't experience this first hand, but understand this concept to be a fairly accepted. I don't think these are typical bolt head markings, but I learn something new everyday.

[Owen L.]

Re: 1967 Bolt head ID and application

Here are the bolt heads on my unrestored '67 that I've owned since 1980. Only the upper driver's side has any obvious marking but all have recessed heads. (I don't recall if these hinges have ever been painted.)
IMG_2903.jpgIMG_2906.jpg

[Garry B.]

Re: 1967 Bolt head ID and application

Owen, I agree with your assessment of recessed heads because that is what I have seen over the years as well. I have to make a correction. I said that my photo is of the lower hood support, but it is in fact the lower hood hinge support. Sorry for the confusion. These "triangle" marked bolt heads are in many places on my car and it's puzzling why the originals would have been replaced. BTW- the car is not a frame off restored car, so that can't be the reason either. Thanks for your response.

[David B.]

Re: 1967 Bolt head ID and application

When asking about bolts if you could supply a part number a lot of guess work would likely be eliminated.

[Richard M.]

Re: 1967 Bolt head ID and application

When asking about bolts if you could supply a part number a lot of guess work would likely be eliminated.

David, The part# is 3847758 SCREW ASM (AIM UPC 11-13 Sheet B6)

They're similar to what was used to attach the seat tracks to the floor, 3847757(AIM UPC 1 Seats Sheet J5), also SCREW ASM, likely a different length. IIRC both are 5/16" Course thread.

Owen, I agree with your assessment of recessed heads because that is what I have seen over the years as well. I have to make a correction. I said that my photo is of the lower hood support, but it is in fact the lower hood hinge support. Sorry for the confusion. These "triangle" marked bolt heads are in many places on my car and it's puzzling why the originals would have been replaced. BTW- the car is not a frame off restored car, so that can't be the reason either. Thanks for your response.

Garry, Those hinge attach bolts you show are not the typical integrated bolt and washer like in Leif's and Owen's photos. Not saying they're not original, just not typical.

I did some searching and the Triangle symbol is the manufacturers mark, Infasco in Canada.

See page 12 of the pdf below(can't upload....too big)

https://www.electronicfasteners.com/wp-content/uploads/2014/09/northamericanmfgidentificationmarkings.pdf

Rich

[Dick W.]

Re: 1967 Bolt head ID and application

I recently bought a two owner, 46K mile '67 and have been assessing the overall originality of the car. The prior owner made some small but non-original changes that I have found so far, but in looking at the bolt heads I am scratching my head. I have found many bolt head M, L, TR and others in the right places, but this one has stumped me. I have found these bolt heads with triangles in many places that should have had not reason to be replaced such as the female hood latch to firewall and this one that attaches the hood support arm to the inner fender. Before I assume they are not original, can anyone tell me if they have ever seen these used? My car was built on February 1, 1967. Thanks for any insight you can provide.

I stand to be corrected but the bolts in question are Premier (brand) fasteners. To the best of my knowledge they were not suppliers to GM but they were suppliers to many dealerships. My guess is that the hood has been off your car in a dealership

[Joe L.]

Re: 1967 Bolt head ID and application

David, The part# is 3847758 SCREW ASM (AIM UPC 11-13 Sheet B6)

They're similar to what was used to attach the seat tracks to the floor, 3847757(AIM UPC 1 Seats Sheet J5), also SCREW ASM, likely a different length. IIRC both are 5/16" Course thread.



Garry, Those hinge attach bolts you show are not the typical integrated bolt and washer like in Leif's and Owen's photos. Not saying they're not original, just not typical.

I did some searching and the Triangle symbol is the manufacturers mark, Infasco in Canada.

See page 12 of the pdf below(can't upload....too big)

https://www.electronicfasteners.com/wp-content/uploads/2014/09/northamericanmfgidentificationmarkings.pdf

Rich

Richard and Garry-------


The bolts pictured are not GM #3847758. While, theoretically, those bolts could have been of either trimmed head (non indented) or non-trimmed head(indented), the 3847758 were bolts of GM 275-M material grade and phosphate finished. The bolts pictured are GM 260-M or ungraded.

You can easily confirm this: remove one of the bolts. If the flat washer is not a captured washer and/or if the bolt does not have a pointed tip, then, for sure, these are not original bolts.

[Garry B.]

Re: 1967 Bolt head ID and application

Guys, I appreciate all of the great information on these bolt heads. I honestly didn't and don't think they are original after reading all of the posts. Easily fixed, but not knowing '67 that well yet I didn't want to remove originals until I knew for sure. Thanks again everybody. Garry

[Joe L.]

Re: 1967 Bolt head ID and application

Guys, I appreciate all of the great information on these bolt heads. I honestly didn't and don't think they are original after reading all of the posts. Easily fixed, but not knowing '67 that well yet I didn't want to remove originals until I knew for sure. Thanks again everybody. Garry

Garry-------


Do keep in mind that while these are not the bolts originally scheduled for the application, the possibility does exist that, for one reason or another, the factory ran out of the scheduled bolt and substituted these bolts. This is certainly not a critical fastener and a substitution could be a possibility. Certainly, the factory was not going to shut down because they ran out of the AIM-specified bolts. So, it's remotely possible these were the original bolts used. The problem is that I highly doubt they would ever be considered as typical of factory production as far as NCRS standards are concerned.

[Garry B.]

Re: 1967 Bolt head ID and application

Joe, having been down the judging route many times I can relate to your sentiments about the "not typical factory production". I highly doubt that these are original to my car because I have found them in a few other places and sizes on my car, so each one I find further diminishes the notion that they are original. At least I now know with very little doubt that they need to be replaced with typical factory bolt heads which I will do over time. Thanks again.

[Joe L.]

Re: 1967 Bolt head ID and application

Joe, having been down the judging route many times I can relate to your sentiments about the "not typical factory production". I highly doubt that these are original to my car because I have found them in a few other places and sizes on my car, so each one I find further diminishes the notion that they are original. At least I now know with very little doubt that they need to be replaced with typical factory bolt heads which I will do over time. Thanks again.

Gary------


While I do not think it's the case here, some cars have been made non-original in order to make them "original".

[Garry B.]

Re: 1967 Bolt head ID and application

Joe, I think I know what you mean and this is for sure not the case with my car. It received a repaint of it's original Elkart blue paint back in 1988, so a real possibility some of these were replaced then. On a side note, on Paragon's bolt head chart, there are two bolt heads that match some of the bolts I am finding. If I remember correctly, both on the chart are grade 5's but they do have the triangle. However, the listed application is different than the application on my car. It's clear that not all bolts are represented on this chart of which I don't think they claim it to in the first place.

[Joe L.]

Re: 1967 Bolt head ID and application

Joe, I think I know what you mean and this is for sure not the case with my car. It received a repaint of it's original Elkart blue paint back in 1988, so a real possibility some of these were replaced then. On a side note, on Paragon's bolt head chart, there are two bolt heads that match some of the bolts I am finding. If I remember correctly, both on the chart are grade 5's but they do have the triangle. However, the listed application is different than the application on my car. It's clear that not all bolts are represented on this chart of which I don't think they claim it to in the first place.

Garry------


If you have any of these "ungraded" bolts in chassis applications, I'd definitely remove them and replace them with, at least, properly graded fasteners. Most chassis fasteners are considered safety-critical and are virtually always GM 280-M or 300-M (SAE 5 or 8). I don't think there's any way the factory would ever have, by substitution, used an "ungraded" fastener in a safety-critical application.