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.

 

[Hemikiller]

Ford driveshafts are measured center to center of the u-joints. There are two 1973 C6 driveshafts used depending upon the gear ratio of the rear axle. Both are 47 7/32 inches center to center. The 3.25 and below shaft takes 1310 u-joints and is 3" in diameter, the 3.50 rear shaft takes 1330 u-joints and is 3 1/2" diameter.

The factory issue C6 1310 yoke is 8 7/32" long from the center of the u-joint to the tip, the 1330 is 8 5/32".