Driveshaft length

[Bullerman]

Can someone tell me the driveshaft length on a 50 Ford Custom. With the three speed. It seems like one in the car is a hair too short.
I have a vibration above 45. I changed universal joints.
I took it to a shop yesterday. He is going to check and make sure it's not bent. He asked me if it was the driveshaft that came in the car.
He said it looked like the part that goes up in the transmission was a little short. Just trying to find out what length it should be.