SoCal_gixxer

I just installed a dented tank in my 06 gsxr600 and it doesn't seal as good as the stock one. So now whenever I do endos, gas leaks out of both the runoff hose and out of the actual cap all over my tank.

How can I fix this?
Do I need a new tank or can it be fixed?
Will a race twist off cap fix the problem?

Any help will be greatly appreciated