Thanks for all the great suggestions folks !
I measured my camber with a framer's bubble level (24" long), a small ruler and simple trig
All measurements are on the rim, not the actual tire.
I read on a Porsche site that 930's running 11" wide rears were using between 0 and -1 deg camber for tire wear (street use). I realize that they have much more weight in the rear but this may be a good starting point. I think I'll be measuring the tire wear every couple of weeks just to make sure things are acceptable.
I took a close look at the trailing arm mounts by the frame horn last night. Things are a little tight to get a camber box fabrication going but I am looking closer at it. The problem is that the inner area where the pivot bolt actually bolts into looks like it is inside the framehorn by about 1/2".
pic from
www.blindchickenracing.com
If you could get a weld-in irs pivot, it looks like there is room to weld this new pivot ontop of the factory pivot. This would move the trailing mount upwards by about 2 inches .. non adjustable but a move none the less. Not sure if this is too much movement but it would be a start. If it didn't work, you would still have the lower stock pivot intact. Just a thought.
Sandeep