Good way to check for a bad timer base is to index the flywheel for all cylinders (write the numbers for TDC for each cylinder on the flywheel.) and hook a timing light to each spark plug wire. When you point the gun at the timing pointer on the flywheel ONLY the number for the cylinder that you are connected to should be seen. If you see other numbers show up you have a bad timer base (or a bad switchbox).
