How do I edit questions within question groups in a quiz that was migrated to new quizzes?

I did not use question banks in the original classic quiz.  Instead I setup question groups.  But after migrating and assigning, I have found mistakes, including a question with blanks in the multiple choice responses.

In build view, I can only see "# questions pulled randomly from bank: [name of old test - group in that old test] #pts per question"

I can not view the actual questions unless I preview the quiz or moderate a student's completed quiz.  Doing that, I only see the questions that were selected for that instance and cannot edit them.

From moderate, I can regrade for mistakes in the answer key, but I can not edit the question stems and the one question that has a blank in the multiple choice responses will not let me regrade because of the blanks.  

I can edit the question in the quiz that it was migrated from but this does not appear to change the question in the new quiz.  I can find the question in an unfiled question bank, but changing it there does not appear to change the question in the new quiz.

So how do I find where the new quiz is storing the question pools so that I can edit them?