Wheels for 66 barracuda

I went ahead and ordered the american racing outlaw II wheels in the 14"X7" and P205 70 14 B F goodrich radial TA, and I can't be happier with the combo. If it ever stops raining in Kansas city I'll post some pictures. I'm still having a vibration issue however. I noticed one of the front brake drums has a spring around the drum on the driver side, bot none on the passenger drum. What is the purpose for the spring? Could the lack of a spring on the passenger side be a source of vibration?