I've got a 72 240z with L24 and Weber DVG carbs. Car is backfiring through the carbs like crazy when I give the car gas.. possibly lean carbs? This problem just recently started developing where I would be at a light and when I take off it would sputter at first for a few seconds.. then finally have power after it was done sputtering. Only seems to be in lower RPM. I've included a video showing what I mean. The last 6 seconds of the video I hold the throttle where it is stumbling at.
http://youtu.be/Y-EZZRY1A34