1966 barracuda driveshaft length

Hello everyone, Have a 1966 PLYMOUTH BARRACUDA with a 273 motor,904 trans and 8.75 rear end not installed yet still in restoration mode . Have read that driveshaft should be 49.58 length and the other people say that is work and is 51.53 length. Anyone have this set up that can measure center to center and give me correct length. I would appreciate it very much. Thank you Richie