I have been through the smog game for ages. I have a 77 also. You will most likely pass with any dizzy or stockish carb AND as long as: You have your air rail, air pump, stock air cleaner and it runs very well. They do not typically look for EGR stuff. We had a thread going somewhere a while back about this.....
For those of us with 77's we enjoy going through this on a yearly basis so it's just best to get the stuff you need to pass and keep it running well.