Okay, found out my 721 was a 51cm frame. Bit it felt comfy for me. And I'm 5'9. The guy I'm buying the cervelo p2t frame from said the top tube is 54cm and seat tube is 53.5cm. Which makes the frame what size?

Does anyone know the top tube length and set tube length for the 51cm 721 frame? I've alread sold my frame so I can't measure