if you are using your stock torque converter that match book size weight on the front of it is the added balance for the 360---if the weight is knocked off it is then zero balanced---be sure to leave the little postage stamp sized weight alone--that is what is used in initial zero balance----in a big block the big weight means it is going to a cast crank----no big weight and it is a forged crank-zero balance--cant see a reason to buy an expensive flexplate---for the same money your local torque converter rebuilder can set you up with a rebuilt zero balance unit---bob