Why are these steering arms different?

[chevynut]

I have removed several sets of steering arms from frames I've taken apart, and I have just run across an unusual pair. Most of these have casting number 3725619 and 620. The strange set I have are casting number 3737215 and 216. They look different. I did a search and can't find that number anywhere.

Any idea what's up?

The pic below shows the difference.

20130409_001 (1).jpg

[Maddog]

That's a first for me. I have never seen a 55/57 with a different steering arm. 58-64 are all front steer and the arms are considerably different then those. Bolt hole spacing is the same from 55 to 64.

[Rick_L]

One of them is going to have a bump steer problem.

Never knew of any differences.

[chevynut]

I actually discovered today that there are 3 different steering arms for these cars.

3708191 and 3708192
3725619 and 3725620
3737215 and 3737216

They're all slightly different. The 370819X parts are pretty close to the 37256XX parts, but they are different.

I'll post some pics when I find my camera.