Another Drive Shaft Length Question

I have moved the rear end back 1" for more tire clearance.

Now I have a question on the Drive Shaft Length.

Here is what I have.

The Drive Shaft measures 48" center to center of U joints.

With the Slip Yoke pushed all the way forward and bottomed out on the 727 transmission output shaft, the center to center measures 49 1/2".

This gives 1 1/2" of travel. Is this too much?

The Slip Yoke has 4" of internal splines from the U joint end.

This would leave 2 1/2" of splines on the output shaft.

Should I have another drive shaft made with 48 1/2" center to center?

Herb