Motor is popping back through the carb... Help!

If you can't find any bent pudhrods I would bet that you lined up the wrong mark on the crank timing gear. There are a few marks on the gear and it can be confusing on which is the correct one, especially in low light. If you did use the wrong mark and the engine runs good until you start to open up the throttle, the engine then starts to pop through the carb. Take your breather off, start the car, then stomp the throttle. If you see a mist blow out of the carb and it does it over and over, I would bet that the timing mark used was the wrong one.

Jack