I learn stuff everyday. After all these years I didn't realize there was a difference between the 10 and 12 bolt rear upper control arms. ILT offers the two. Can anyone explain the difference? The bushings are all the same correct?

 

See this >>> https://classicoldsmobile.com/forums...utlass-123231/

 

Joe & others have addressed this topic (above). This image is simply to provide clarity RE: Part Nos.

 

I just put those (12 bolt ones) in my car this week. I had to grind off a bunch of metal off the control arm top get it to fit on the pumpkin side...

Pat

 

12 bolts on cover and type O?

 

Yes. I think it was more because of poor quality control more than anything. You can see how it was not the same on the end

 

Yes I can....

 

12 bolt has a 8.875 ring gear all others are smaller diameter 8.5 making the casting bigger hence the area where it rubs is where the ring gear is. casting buldges and that is why the control arm rubs.
Hope that makes sense.

They used the metal to reinforce so that there was enough rigidity to do the job.


Jim
JD Race