Voids allow the rear subframe to articulate. It's basically a hinge in the middle where the hinge is the rear subfrom blocks to dif. Mild four wheel steering in effect. The side load on the car makes the outer edge of the bush flex into the void hole. This allows the rear wheels to follow the line if the front wheels more accurately.
Problem is its too flexible for spirited driving. Fine for the executive comfort of the design brief, but throw it into a corner and the play is taken up with an alarming sensation of sideways movement IMO. It leaves you with a "wtf was that" feel. Did it slide? Did it tram line? Did something brake at the back... No its only bush play again. Sigh...
The Carlton bushes, although they refused to stay fitted, gave a very satisfying firm feel from the rear of the car.
A thought occurs though...(o-oh) the poly al has are for Monaro I believe...? These are same as Carlton, I also believe. So my concern is that they also may work loose as mine did. But as Al pointed out, his are fitted with the thicker top pad as well. So even if the bush did have a tendency to work out, it can't because the thicker top pad prevents it.
Carlton bushes are spaced differently to omega due to the height the bush is set on the centre spacer. So the bushes must be fitted as a set, not just the bush but the top pad as well. Something I didn't do when fitting Carlton bushes. Maybe they would have stayed in with the top pad fitted as well.
As I understand it though, as the bush is set higher on the centre spacer, this means the chassis will be raised from the subframe by that amount. 10mm or so I think. Not sure what effect that will have, if any.

Did I see there are very small void holes in the poly? And does this mean they are directional?
