What program are you using for capture? It may help to use something that has the option to dynamically resample the audio, so the framerate is fixed to 29.97 and audio sync can be maintained without dropping frames. Check out VirtualVCR.
It's inevitable that you will get dropped frames from a poor source like an old VHS or 8mm tape, but laserdisc should not be problematic. You can check by capturing from a DVD player, and see if you still get dropped frames.