Carlo,
Oleyeller speakith the truth. I went through the samething saying, "this can't be right!." Mine is offset about 3/4 of an inch to the right. However, my concern was that my drive shaft angle was going to be too steep due to the very short distance is was going to run. Went to Tom Woods web site and found a ton of info on drive shafts and had him make me one up.
The only thing I found that was cause for concern was to ensure that the centerlines of the engine/transmission and that of the rear end pinion shaft were "parrallel and non-intersecting lines." This way the U joints can do their job of "smoothing" out the natural oscillations that take place between the two U joints.
Tom's link is
http://www.4xshaft.com
click on his "technicial info" button
- Jim -