OK, I just measured the stock uppers on my 78 Grand Am, they are 10-7/8" center to center. Checked it 3 times. I am not sure why the Jegs arms would be 11-1/4" unless some G bodies were made a little different. Here is a link to the Jegs arms:
http://www.jegs.com/i/Jegster/550/40088/10002/-1 -Jim