Since the rear is out, I am going to replace the upper bushings in the ears of the center section. The new bushings have a hard rubber ring on them. Does this get slid all the way on the bushing (towards the left in the picture) before driving the bushing into the rear? My stock bushings did not have these rubber rings.

Are those the ones from Metco ....... if I recall those rings go on after you install bushing not really sure what they did,just a spacer in a 66 I had to trim them to fit as they close to housing in one area .......have since gone to different bushing .not sure if that helped or confused you

I have never seen a ring like that on bushings...

Except for with poly bushings. If this is like poly you save the ring and put it on the bushing after it is pressed in. That keeps the poly bushing from walking out of the shell (it has a shoulder to keep it from going the other way).

I would probably treat it the same way even if it is rubber. It *IS* rubber isn't it? ;)

I believe these came with my Edelbrock adjustable uppers a couple of years ago. I just never installed them. They are poly bushings and that ring is just rubber or maybe it is poly?? Slides on/off easily. I can't see what it would do if I slid it on after the bushing was pressed into the rear?? And, it is a bit too thick to go on before, because it goes past that lip on the bushing where it stops in the ear of the housing. It would prevent the bushing from going all the way on by about 1/16".

EDIT>>>> Found the info. Edelbrock calls that piece a poly thrust washer and says to install it on the inboard side. So the bushing gets pressed in first, then you slip the ring on , then the upper arm bracket goes over that.
Look here...page #2, figure #3, note #2. Edelbrock instructions (http://www.edelbrock.com/automotive_new/misc/tech_center/install/5000/5268.pdf)
They made no mention of it in my kit, I found it by looking at a different kit part number that had the same bushings in it.

...They are poly bushings and that ring is just rubber or maybe it is poly??
Exactly as I suspected and even goes right where I suggested. On a rubber bushing the rubber is bonded to the outer metal shell. Not so on a poly bushing. So a poly bushing can work itself right out of the shell towards the outside. I have one like this on a lower control arm right now that needs the extra ring installed on the inside (did not have it when I installed the bushings, long story).

That "thrust" washer preloads the arm, and thus the bushing load, towards the inside and keeps the bushing inside the shell where it is supposed to be.
...I can't see what it would do if I slid it on after the bushing was pressed into the rear??
It fills the space between the ear and the arm.

Steve, now it makes sense. Thanks for the explanation.:)