I aske Kei Iinuma for comments as he does not follow this forum. SAAC members may know him as the owner/driver of #007 Series 8000 that has driven around visited all 50 States and been on the track at numerous SAAC conventions. He and his wife load the Cobra with all their luggage and necessary tools or trips around the country. His comments:
This situation may be a lot more complicated than moving the transverse spring slightly to the left.
1. If one should be able to move the spring to the left, this will cause the top of the tire to move outward, changing the camber, positive. At the same time, the opposite will be true for the right rear tire. If you can move the spring left, the right rear wheel will have more of a negative camber.
2. Theoretically, if the transverse spring were attached incorrectly, the lower control arms would also have been attached incorrectly and unless they are adjustable, as they are located on the frame, they are independent of the rear diff / spring and will also have to be corrected at the same time.
3. Without first ascertaining frame correctness ruling out an off-squared frame the transverse spring may NOT be the problem.
4. I would not start with the spring. First find out if the frame is square, then measure to see if the rear differential / spring is centered and if it is the tire rubbing problem is not from a misaligned rear differential / spring perch.
5. The problem may simply be a body mod fix. If it is a glass body, the form may be off. If aluminum, then he can simply bang the body out a bit?
Take the car to a reputable frame straightening outfit and confer with them regarding the squareness of the chassis before touching the mechanicals.
Re-arching the spring is the traditional, accepted and proper way to go.
I use Gabriel Hi-jacker air shocks in the rear because we overload the Cobra with a trunk full of luggage, tools, and extra parts when we travel cross-country. I put in 150 psi in the shocks to eliminate bottom-outs and release the air to 25 psi when I race the Cobra.
I run Yokohama 225/45/15s all around. They look kinda goofy because they don't fill the wheel well as well, but they are awesome on the track and from the front the little 289 looks very purposeful.
Again, it is not recommended that the transverse spring and attendant mechanicals be experimented on to gain the half inch or so needed to eliminate the tire rub. Look for and try other non-evasive tactics on this car.......that is the Cobra, a culmination of almost a century of experimentation on the transverse spring design may not like to be messed with.
Don, if you want to, pass this info on.
Kei