Positive Camber Impossible?
Not enough to have an appreciable effect on caster. You're talking less than .5 degrees. I've done it.
RRR, perhaps you can give me the scientific explanation for this then: I'm running eccentric UCA's on my Valiant (installed correctly, NOT per the Moog instructions). It has P185/70/R13s on it, and with the LCA's jacked up too high by the alignment shop, they were able to get about 1.5 degrees of caster dialed into it, with about .5 negative camber. Like this, the car acted squirrlier than a Chip and Dale cartoon. Also pulls a bit to the right.
With P215/75/R14's on the front - without adjusting a single thing from the above - you could practically drive hands off. It would track dead center and turning left or right would result in the steering wheel coming back to center perfectly. Granted, the back of the car was now about 2" lower than previously, as the 13's were still in the back.
Since the 14's were only a test (those P215's were running on dangerously narrow 4.5" SBP rims), I put the original 13" wheels back on with the P185's, then dropped the LCA's down 2" since. It's still uncomfortable and pulls to the right a bit, but it's more controllable and predictable. I also get a bit more self-centering through tight turns, but not enough.
Perhaps a trail issue rather than than caster? Either way, I'm rather convinced the tire diameter is amplifying (or decreasing) some element of the suspension geometry, but I'm not going to rest until I know the exact science behind what's going on.
My bet is that more than a few of us may have a base-model A-body on factory 13's that would make for nice daily drivers/beaters as-is, but do not necessarily justify SBP 14" wheel swaps.
-Kurt