The easiest way for the novice to set pinion angle is to install all of the drivetrain...(unwelded perches)jack the car up until the drive line is level, be sure to use jackstands, Then simply rotate the rear end housing down to the desired angle. 5-10 degrees for leaf springs, 1-3 degrees for ladder bar or 4 link. Ideally you like to see 0 degrees in a full race car at speed, but the gains for this are very minimal. I use one of these inclimeters found at most hardware stores for setting angles, they are inexpensive and do the job quite well.