JB: Sorry I missed your question in this forum.
The 14th simply codified the 1st Reconstruction Act and subsequent state laws on the issue of disfranchisement through the 2nd and 3rd provisions of the Amendment. The text of the 14th Amendment can be found on Wikipedia here:
As for specific laws on the issue, read pages 431-435 in this volume:
It depends on who you read as to the effect of disfranchisement in the South. Everyone admits it happened, though many progressive historians place the number artificially low. It certainly helped swing the 1868 election in favor of Grant, that along with voter fraud in favor of Republicans in States under military reconstruction. Grant never would have carried NC, SC, AL, TN, FL, or AR without disfranchisement and fraud, and of course TX, VA, and MS did not qualify for the election. It is safe to say that the strict voting provisions in many States during the Reconstruction period–for example requiring the “iron-clad oath”–curtailed white Southern participation in elections, particularly from the old political class.