63 to ? lower control arm shaft ?

[Stan E.]

What years are correct for 63 lower control arm shafts? Thanks!!!

[Philip C.]

Re: 63 to ? lower control arm shaft ?

Hi Stan the 63 up shafts are the same (to 82), but the lower control arm on 63s from beginning to late 63 have no reinforcement welded on. Phil 8063

[Joe L.]

Re: 63 to ? lower control arm shaft ?

Phil and Stan-----

Yes, all the 1963 to 1982 lower control shafts were the same part number and, even, the same forging number. However, curiously, the shafts are not all configured exactly the same. On some of the shafts, the main beam section has an "I-beam" configuration (i.e. longitudinally "dished" on both sides). On other shafts, the main beam section is "flat".

I have never been able to figure out how shafts which appear to be completely different forgings have the same forging number, but that's how it is. The forging number of 3738505 appears on both shafts.

I believe that these shafts were used interchangeably over the years, but I have nothing "scientific" to support that theory. However, I do THINK that the "flat" shafts were used PREDOMINANTLY (or, even exclusively) during the 63-69 period and, sometime after that, the "I-beam" shafts came into PREDOMINANT (or, even, exclusive) use. I have heard of one case of an apparently original car that had one of each shaft on the car. I do not recall what year the car was, though.

I can say, for sure, that the original shafts on my 1969 were "flat". I can also say that of all the NOS shafts that I have, all of the "flat" shafts were supplied in generally older GM packaging and all of the "I-beam" shafts were supplied in generally newer GM packaging.

Very curiously, I have one NOS shaft of the same PART NUMBER (GM #3749296) that dates from the very late 50's (these exact same shafts were used on 58-64 full size Chevrolets; in case some don't know it, the 63-82 Corvette front suspension was very similar to 58-64 Chevrolet passenger car front suspension). Anyway, this shaft's beam section has a ROUND configuration, although I don't think that any of these were ever originally used on a Corvette. So, there were THREE different configurations for the GM PART NUMBER 3749296 shafts.

A photo of the shafts is seen below and I'll post 2 other photos in separate posts. The ROUND configuration example is too hard for me to get at right now and I think that it's irrelevant for Corvettes, anyway. I mention it just for curiousity.

I'd be very interested in hearing reports on what shafts folks find in their cars and what years those cars are. It's pretty easy to check this out. It should only take a few minutes.

[Joe L.]

Additional Photo

Here's the opposite side of both shafts.

[Joe L.]

Additional Photo

Here's a close-up of the FORGING number area of both shafts. Although it may be a little difficult to see, you will note that the 3738505 forging number is the same for both shafts.

[Harry Sadlock]

Re: Additional Photo

1963 - 13,3XX, Flat Shaft Right and Left

Harry

[Kevin M.]

1967 Flat

Dec 66 built flat.

Kevin

[Stan E.]

THANKS GUYS!!! NM *NM*

[Chris D.]

63, I-beam, 11,0XX *NM* *NM*

[Bill Lynch]

Re: Additional Photo

'63 #16224 .. one of each. They are original to the chassis.

[John G.]

Re: 63 to ? lower control arm shaft ?

Joe ..
My car is an early production '64 that has both a 'flat' and an 'I-beam' lower control arm shaft. AFAIK, or can discern, these appear to be original installations on the car. Though I have owned this car for almost 35 years I didn't purchase it new so I can't be 100% certain, of course. ..

I always thought it peculiar that these shafts differed in their design to one another and chalked it up to a 'left' vs. 'right' configuration - though dimensionally they appeared to be the same.

John

[Joe L.]

Re: 63 to ? lower control arm shaft ?

John------

As I mentioned, I believe that these 2 designs were used interchangeably. From what you and Bill have reported, it appears that "one of each per car" is more common than I thought. Here's what I THINK likely occurred: during the 63-64 period, there were a LOT of these shafts being used. During that period, they were used on not only Corvettes, but also passenger cars. So, there was probably at least 2 suppliers of the forgings----one or more manufactured one design, one or more manufactured the other design.

You will note in my photo of the forging number area that the "flat" shaft has a "C" between the forging number and the other numbers below. The "I-beam" shaft has what appears to be a circle with some other character inside it (somewhat like an @ symbol). My guess is the "C" and the "@" symbol are the forging manufacturers' ID's. I have no idea what they represent, though.