73, 351C/C6 drive line

[lynn]

I received 2 drive lines and yokes with my Mach1. I have a 351C/C6 that I'm going to use. One drive line is 51 3/4" X 3" end to end and the other is 52 3/8" X 2 3/4". I also have 2 yokes one is 5" and the other is 6 1/2 " both fit in the C6. Which drive line and yoke are for my 351C/C6 combo? Thanks

 

[giantpune]

I just measured the original driveshaft out of my 351C/C6 car. Its 47" between the center of the U-joints.
I can't measure the yoke, cause its currently back in the car. This is a picture of it if that helps.