Good Afternoon everybody!!

I have a HobbyPro Ford GT and today while putting around the street, and I do mean putting, the engine started to act like the choke was in the on position. The car will try to fire but I noticed that it was backfiring out of the carb. Upon futher inspection It looks as though a rock or object was sucked into the flywheel housing and some how lodged itself between the flywheel and the Mag leaving a nice gouge in the flywheel before freeing itself to continue on its journey. With the engie wanting to fire yet back firing from the carb I think it some how advanced the timing. Is this plausible? What do I need to do to reset the timing?
thanks in advance!!

Jason