What makes 63 lower A-arms different from 64 A-arms? Thanks
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Re: What makes 63 lower A-arms different ?
stan------
The difference is the lack of a welded-in reinforcing plate on the 63 arms versus the 64 and later.In Appreciation of John Hinckley -
Re: What makes 63 lower A-arms different ?
Late build '63s have the reinforced front lower A-arms. Off the top of my head, I'm not sure of the production date/VIN changeover range, but it might be in the JG.
Boyan Brkic has researched this issue. His late build '63 had one of each and he replaced the non-reinforced version with a reinforced version.
I'm not convinced that his car was NOT built with the two different versions. As would be the case when the disposition of superseded parts is "use until stock is depleted" there could have been a period in production where both versions were used indiscriminately.
My hunch is that the change originated with the full size car engineering group, and since the Corvette is much lighter up front than a 409 Impala, it's not a critical issue on Corvette for normal road use.
DukeComment
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Yes...
and the change over wasn't 'clean'... I've seen more than one original car from the early calendar year 1963 era (Jan-Mar) equipped with an early style A-arm on one side and a late style on the other side. This suggests the two versions of the arm were binned together and pulled from inventory at random...Comment
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Anyone have a picture of the added part? *NM*
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Re: Yes...
Hey guys, I have done alot of research on this as Duke said. I have a Mid May 63 built car. When I bought the car, it had one of each of the arms. I spoke with the original owner and he verified he did replace the one in question with a newer style one from GM because when a ball joint went out, you could only buy the whole assembly. So I beleive my Mid May car originally did not have the reinforcement.
I have looked at alot of original cars over the last few years in order to determine a cut off date for the change. It is not listed in the judging guide. The last super original car WITHOUT the reinforcements was in the range of VIN 19600. After about VIN 20,000, all cars that I have seen which I beleive to still have the original parts on them have the reinforcement added.
I do agree with Duke that there was a transition time and we could have a mix of parts. As for my car, I beleive that it did not originally have the reinforcement on either side.
Not to add to the confusion, but the cross shafts are also different. Very early cars have a "H" beam type cross shaft and the mid to late production cars have smooth shafts like 64 and up. I think the changeover was about VIN 6000, but I am not as sure as I am for the reinforcement. I have also seen original cars with two different types of cross shafts and the same, NON REINFORCED lower control arm.
I have a good diagram on what the reinforcement looks like and I can send photos of what the cross shafts look like, but I still cant figure out how to post images here on this site. If anyone needs them either call, 818 227-9533 or email me at bbrkic@msn.com
Incidently, Americas Finest Corvettes is reproducing the 63 non-reinforced control arm. I have not seen it to see how accurate it is, but it is available for about $300.
BoyanComment
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