727 yoke not far enough in?

thought i would hijack this thread. as i too am questioning this here is a picture of my current shaft.

I am getting some vibration around 50mph.

i have a ebody big block 727.

I have about 1 3/4 of travel to bottom out the sleeve. When i go to bottom out the sleeve to measure it it bottoms out on the splines on the back of the output shaft, not on the face of the transmission. is this ok? I have an 8" yoke looks like. is that the correct yoke?