C2 front shock upper nut: Difference between GM #043469 vs GM #1365067

[Gary B.]

Thanks,


Gary

[David B.]

Re: C2 front shock upper nut: Difference between GM #043469 vs GM #1365067

'63 #043469 is a Delco Products part number (Dayton) and '64 #1365067 is a Buick part number. Based on this alone I doubt they are similar.

[Gary B.]

Re: C2 front shock upper nut: Difference between GM #043469 vs GM #1365067

David,

I suspected the 43469 part number was a very old one that predated Corvettes.

Gary

[Joe L.]

Re: C2 front shock upper nut: Difference between GM #043469 vs GM #1365067

David,

I suspected the 43469 part number was a very old one that predated Corvettes.

Gary

Gary and David------


Yes, GM #43469 is a VERY old part number. It dates back to the 1940's, if not even further back. It was a 3/8-24 and it was used in some way connected to shock absorbers but that's about all I know about it. It was used for front and rear shock for 1955-60 Corvette among many others. Once available in SERVICE it was discontinued in March, 1961. It could be that it continued to be used for PRODUCTION applications after that time but I seriously doubt it. GM says that it was used in PRODUCTION for the front shock upper nut for 1963 Corvettes but I actually doubt it.

When the 43469 was discontinued from SERVICE it was replaced by GM #839103. That's also a very old part number. It was used for 1961-62 Corvettes for the front and rear shocks. It was also used for the engine connecting rod bolt nuts for 1955-61 Corvettes. It was discontinued from SERVICE in April, 1962.

The 839103 was replaced for SERVICE by GM #3784628. It was discontinued from SERVICE in December, 1966 and replaced by GM #3866766. The latter was used as the rod bolt nut for all Chevrolet small blocks with 3/8" rod bolts.

GM #3866766 was discontinued from SERVICE in October, 1994 and replaced by GM #225854. The latter is available from GM to this very day.

GM #1365067 was used in PRODUCTION for the front shock upper nut for 1964-82 Corvettes. It was available in SERVICE until April, 1975 when it was discontinued and replaced by the GM #225854. I would not be at all surprised if the 225854 was actually used in PRODUCTION for the front upper shock nut from about 1975 to 1982.

I believe that ALL of the above-referenced nuts were HEAVY DUTY nuts. This means that they were thicker than a standard nuts and were about 21/64" in thickness. I believe that all were phosphate-finished and visually similar except for the 1365067. I believe the latter was completely flat on both sides, meaning that the points of the hex were not tapered. I believe that all of the others had tapered points on at least one side and I am certain that the 3866766 and 225854 had tapered points.

[Gary B.]

Gary

[David B.]

Re: C2 front shock upper nut: Difference between GM #043469 vs GM #1365067

I might be missing something here: 043469 is a common correct 6 digit part number assigned and used by Delco. 43469 a 5 digit number is a mystery to me.

[Gary B.]

Re: C2 front shock upper nut: Difference between GM #043469 vs GM #1365067

David,

Thanks for that clarification. I didn’t know you shouldn’t drop the leading 0.

Gary

[Joe L.]

Re: C2 front shock upper nut: Difference between GM #043469 vs GM #1365067

I might be missing something here: 043469 is a common correct 6 digit part number assigned and used by Delco. 43469 a 5 digit number is a mystery to me.

David------


The leading zero was added somewhere along the way; it was originally just 43469. As I mentioned, this is a part number that dates back to at least the 40's. The leading zero was probably added when GM went to 6 digit part numbers. There were once 4 digit part numbers and, probably, 2 and 3 digit part numbers, too.

[Gary B.]

Re: C2 front shock upper nut: Difference between GM #043469 vs GM #1365067

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Gary

[Joe L.]

Re: C2 front shock upper nut: Difference between GM #043469 vs GM #1365067

Some of you may never seen an original front shock upper nut (for ‘64-‘82), GM #1365067, since they seem to be exceedingly rare based on my observations. And that nut is not reproduced. Here are examples of that nut from two cars. The first photo is the nut on a ‘66, 5-star Bowtie car. The second and third photos show the nut on a ‘63 that I recently judged that the current owner has owned since 1974. (The yellowish color in the second photo is from the camera flash.) The owner of the ‘63 says the shocks were replaced, but it’s possible that the nuts are original. The nut in photos two and three have the exact characteristics of GM 1365067, however, the ‘63 AIM says the upper shock nuts used for ‘63 were 043469, not GM 1365067. Which is a source of puzzlement.

[ATTACH=CONFIG]111532[/ATTACH]

[ATTACH=CONFIG]111533[/ATTACH]

[ATTACH=CONFIG]111534[/ATTACH]


The last two photos show an NOS GM #3866766 nut on the left (which is designed to be a connecting rod nut), and the nut on the right that was created from a 3866766 nut by machining down the top and bottom surfaces to match the 0.3125” thickness of the 1365067 nut and to eliminate the peripheral chamfer. Fortunately, the donor nut, 3866766, is thick enough to begin with that the two chamfers can be completely eliminated and still leave 0.3125” thickness.

[ATTACH=CONFIG]111535[/ATTACH]

[ATTACH=CONFIG]111536[/ATTACH]


Gary

Gary------

Where did you get the 0.3125 thickness spec for the GM #1365067? Did you measure a known-original nut or get it some other way? GM says the spec was 11/32" (0.344").

[Gary B.]

Re: C2 front shock upper nut: Difference between GM #043469 vs GM #1365067

Joe,

I must have gotten the thickness spec from postings on the DB. And if I remember correctly, one of those posting was yours.

Gary

[Gary B.]

[Gary B.]

Re: C2 front shock upper nut: Difference between GM #043469 vs GM #1365067

Joe,

These are from my research notes on GM 1365067:




Jun 15, 2013 camaros.org







Gary

[Joe L.]

Re: C2 front shock upper nut: Difference between GM #043469 vs GM #1365067

Joe,

These are from my research notes on GM 1365067:

May 1, 1999 NCRS DB posting, Joe said: “This nut, GM #1365067 and long-ago discontinued, was a 3/8"-24 nut of 5/16" thickness with phosphate finish.”


Jun 15, 2013 camaros.org DB posting, Ed “Bert” Bertrand said: “My 69 Corvair still had its original spiral shocks on it when I bought it. I had to replace them a few years later (one was leaking), but I kept them anyway. Here's a picture of the original nut! You'll note it's (approx) 5/16" thick, but UNLIKE a regular not, there's absolutely NO bevel on the edges. Straight cut all the way around. The part number for the Corvair (and most all GM products of the 60's) is the same, so I'm certain it's "correct". All 4 shocks have the same nut on them.”


Aug 7, 2013 NCRS DB posting, Joe said: “The GM #1365067 was 3/8-24 X 5/16" thick”


Oct 28, 2020 NCRS DB posting, Joe said: “The original GM #1365067 was 5/16" thick (standard thickness), zinc plated, and with completely flat ends.”

Gary

Gary------


I think the confusion was caused by the fact that there are varying descriptions of the 1365067 nut in various GM references I have. I expect that the 5/16" thick and phosphate finish came from one reference and the 11/32" and zinc came from another. However, it's very possible that the specs for the nut changed over time and that's the reason for the differences.

One thing that does surprise me, though, is that GM considered the 1365067 a "heavy duty" nut. Usually, "heavy duty" nuts are distinguished from "standard" nuts by greater thickness and/or larger wrench size for a given thread size. However, standard 3/8-24 nuts are 5/16" thick. So, the 1365067 at either 11/32" or 0.314" would actually be thinner than a standard nut and at 9/16" across-the-flats it's the same as a standard nut. So, why would GM then consider it a "heavy duty" nut?

[Gary B.]

Re: C2 front shock upper nut: Difference between GM #043469 vs GM #1365067

Regarding the thickness of GM #1365067, I know of another GM nut, GM #134551, for which one end surface has the typical peripheral chamfer, but the other end surface is completely flat. (Such nuts with one flat surface are commonly seen at the base of the stud with the rubber bumper on top on C2 female hood catches, with the bottom, completely flat surface of the nut adjacent to the latch surface.) Fortunately, the GM engineering drawing for GM 134551 is posted on the DB. The thickness range for GM 134551 is 0.178” to 0.193”. The average of that range is 0.1855”, which yields a +/- thickness tolerance of 3.9%. If we assume that GM 1365067 had the same percent thickness tolerance of 3.9%, then if the nominal thickness spec was 5/16”, or 0.3125”, then the upper thickness allowed would be 0.3247”. If on the other hand, the nominal thickness was 11/32”, or 0.3438”, the lower limit on the thickness would be 0.3304”. Based on the measurement of what I believe is a GM 1365067 nut on the ‘63 I saw ten days ago, this would suggest that GM 1365067 had a nominal thickness of 5//16”, since the measured value of 0.325” would be within the 3.9% tolerance (given rounding of 0.3247 to 0.325), whereas if the nominal thickness was 11/32”, the measured thickness would be out of spec. Admittedly, there is an if or two and a fair bit of speculation going on here.

If the calculations are redone assuming the nominal thickness is 0.33”, which is often quoted for 3/8-24 nuts, then the 0.325” observed value would be closer to the 11/32” thickness. And just maybe the nominal thickness is neither 5/16” nor 11/32”, but 0.33”. That would solve the dilemma.

It would be nice to see the engineering print for GM#1365067, since that would answer the thickness question and the plating question (zinc vs black phosphate). But I don’t know if that will ever be possible.


Gary