I have been reading a number of past posts about pinion angle and I must say, I am very confused on the subject. I would like to determine what I need to do to my car, if anything, regarding pinion angle. So I would like to explain what I am doing and hopefully I can get the answer I need. I have pulled the slant six, 904 and 7 1/4 rearend out of my 68 Dart and I will be replacing them with a big block, 727 and a Dana. I also plan on moving the rear end back 1-1 1/2" for tire clearance. What will I need to do to be sure that when the perches are welded on the rear end housing that I have the correct pinion angle and what should that angle be? Will I have to wait until the engine and trans. are in the car to set the angle or can it be done with the entire drivetrain out of the car? Is there any chance the angle on the rearend will be O.K. as-is so all that would need to be done is weld the new perches on parallel to the old perches?