C2 lower A Arm

[Jack W.]

Can anyone tell me if a 79 lower A Arm is the same as one for a 65? Need to replace one and I have seen later parts that are listed for replacments for C2's

Jack W

[William C.]

Re: C2 lower A Arm

Functionally the same, may have some detail differences for a judged car in the Ball Joint and the cross-shaft that bolts to the frame, appearance only, will work fine.

[Joe L.]

Re: C2 lower A Arm

Jack----

The lower a-arms used for 1965 and those used for 1978-82 (which became the SERVICE a-arm for all 1963-77) had only two differences. The first and foremost is a VERY slight difference in the length of the steering arm stop welded to the arm. This difference is virtually indiscernable and creates no functional problem, at all, when the 78-82 arm is used in SERVICE for 63-77 models. The second difference is indiscernable when the arm is mounted on the car. I'm not going to discuss that difference for 2 reasons. First, I don't want to get some "lunacy" started. Second, it's very hard to describe and it's not worth me spending the time to attempt to do so.

As far as a-arm-RELATED pieces go, there were some differences. The configuration of the lower a-arm shaft varied over the years even though the forging number for the piece was the same for ALL 1963-82 Corvettes. Some pieces were "flat" on both sides; others were of an "I-beam" configuration. For the most part, I think that the "flat" style were used early and the "I-beam" style used later. However, they may very well have been used interchangeably over the whole 63-82 period.

As far as the lower ball joints go, there MAY have been a difference in the ball joint style used on the 65 arm and that used on the 79 arm. I believe that 1963 and 1964 ball joints used a non-captured seal which was configured like a "Chinese coullee hat". Early 1965 may have used this style ball joint, too. Later 1965 through 1982 used exactly the same ball joints and these were the captured seal style with black "rubber" seal. Both the 63-65 and the 65-82 style ALL have the "unthreaded extension" outboard of the threads.

[Pete Van Seggern #30920]

Re: C2 lower A Arm

Regarding the lower cross shaft:
My '63 (built late Dec '62) has one of each type. I bought the car in '66 and have no reason to believe one could have been changed out before that.

[Joe L.]

Re: C2 lower A Arm

Pete-----

As I mentioned, I think that it's very possible that the 2 different lower a-arm shaft configurations could have been used interchangeably. Both have the same forging number, too. I would not be surprised, at all, if what you have is original to the car. The a-arms were delivered to St. Louis with the shafts already installed. The left and right assemblies were different, of course. So, a batch of right side a-arms got one type of shaft installed and a batch of left side arms got the other type and that's how your car ended up with one of each.

The upper a-arm shafts were of 2 different configurations, too. Some had rounded bosses for the frame bolts and some had square bosses for the frame bolts. I've heard of cases of known original cars having one of each type. I expect that the scenario was just like I described above. As far as GM was concerned, the 2 different configurations were interchangeable and they weren't concerned too much about having "matched sets" on the cars.