Best place to get door latches
 

Got a 67 that I just replace both door latches (replacements from LMC). Now I can't lock/unlock my doors from the inside. Driver side door on latches every other time, and if it doesn't it seems to bounce of the striker plate (very unpleasant jolt).

Where should i get some new latches? Or is there something I need to do to the new ones to get them to work better?