Brakes not very good..... :(

Thanks for the information and suggestions!!

I have one quick question before I end up with the wrong booster. I found a local "specialty" auto parts store that can get me a booster. His books show that 71 model boosters are different than 73 model Darts. I have a 71 Dart but when we swapped over to the 73 disc (also from a Dart), Dad swapped the booster and all over??????? So when I go to get the new reman brake booster do I need to get the booster for a 71 or a 73???

From "car-stuff" website it shows all 67-71 cars with either drum or disc had the same booster?? So could it be my issues are because I now have a 73 booster on the car???