I'm using my old 275 for physx but since getting it up and running with my 670 neither card will fold. I've looked around for a bit and can't find anyone with my problem so I'll ask here. Is it possible? I was thinking about trying to run them with the v2 tracker but would appreciate if someone could tell me if that would work before I go through the effort. Thanks much.

mixing cards is tricky at best i have found some do not play well together or at all.

use the FAH gpu tracker
 
v7 issue
 The symptom is hanging WUs, and it only seems to happen with mixed Fermi/non-Fermi GPUs. The order in which GPUs are being configured by FAHControl (and thus the GPU ID FAHClient passes to the cores) is not equal to the actual CUDA/OpenCL GPU ID, so Fermi WUs are trying to run on non-Fermi GPUs, and vice-versa. 
 
Won't be fixed either
 
if you need to Run mixed cards use FAH GPU TRACKER
 

stanford won't fix this issue EVER in v7 (as was posted in the v7 bugfix posting)
as was posted on the Folding forums 
 
just don't mix fermi and none fermi
or kepler and non-kepler
 
Other option is FAH GPU tracker v2 (which should work fine)