That's great, but I have another question. If I understand your description, after the House voted in February, the bill was altered (you mention that the Senate passed a "bipartisan substitute" in July). That would render the February House vote moot because the bill had changed (or was amended). If so, did the House vote again on the final version of the bill? Or am I incorrect that the bill in July was different than the bill the House voted on in February?
BTW - The search I did on AltaVista to find that page was : +"civil rights act" +1964 +vote