As long as you do not have any internal problems like burn valves or bad rings, try pouring in a bottle of "Guaranteed To Pass".
I put it in my 76 Sprint and followed the directions to the letter and I passed with now worries. They say on the bottle that if you do not pass they will pay for your testing. Check it out.
I would not try to cheat the system because if you get caught you may have to go to a "Check Only" station everytime from then on. I don't think it is worth the headache.
Also set the timing to factory specs, even if the car runs like trash. The machines that test go by factory settings so stick to them until you get your OK from the state.
Keep it clean