What is p/s pulley size

I'm working on a 1969 340 Dart swinger. I want to put power steering on. I have some pulleys in the shed that are 2 groove for the crank. I measured my crank pulley, and it is 5 7/8 inches measuring the pulley closest to the block. The one further from the block is 6 5/8.The water pump pulley measures 6 3/4 inches. Are these the correct ones?