installing four speed question?

mopar head that looks like a great idea but , I have one question why does the jig look like it leans backwards? Wouldn't you want it to end up leval or does it lean back at an angle like that to mate with the bell housing? Like I said I haven't done one of these since I was in high school and that was a long time ago. Also is that your drive shaft from the cuda laying on the floor? I need the measurement center to center of the ujoint holes so ,I can have my drive shaft cut down. Are you running a 8 3/4 rearend? I did have a 727 and I'm converting to the four speed so, I heard that I'm going to have to have my drive shaft cut down.