The tabs are soft and bendable. Just use a prybar or a hefty screwdriver and bend them away from the stack. I like to use a C clamp on the stack while I remove the center bolt. There is some built-up tension there than can "surprise" you otherwise. If they're real rusty, you may have to cut the center bolt off with a cut-off wheel. After the center bolt is removed, just slowly release the clamp and you should be good to go.
