Power Steering Pump Belt Size/Part Number for A 66 273 with A TRW Pump?

To find my belt size, I postioned the pump in the middle of the adjustment and used a regular tape measure wrapped around the pulley flats. I found Goodyear belts on Amazon that worked well, and had exact measurements. I had first tried using a rope around the pulleys and measuring that, and they came up about 4 inches shorter than I could use.