Wait a second, I was looking at the wrong graph
http://www.ntnglobal.com/en/products...n_064_067p.pdf
Based on Figure 9 moving the block 1 inch would probably reduce torque loss by .5 x2 (for both CVs) = 1%
Now mine are getting worn out, so I'd double that..
So now we're at 2%... almost 1 mpg...