Setting up 8 3/4 with spool

[motorhead440]

I'm trying to set up my 8 3/4 (489 case) for my 70 duster. It seems that when i acheive the correct pinion depth the run pattern is incorrect.The pattern is low on the heel side. Currently the pinion is .016" deep and the pattern is perfect on drive and coast. The backlash is set at .007". The gears are u.s. gear, and the spool came from Moser engineering. I'm also using a solid collar in place of the crush sleeve so i'm aware of the pre-load proceedures for this set up. Any ideas why i can not get a good pattern with the correct pinion depth? One other problem i found is one sadle flange is .010" taller than the other, that is, one side is taller than the other when measuring from the flange with a depth mic to the bottom of the bearing seat. I don't know if this is critical or not, but i'm not comfortable with it. Any ideas? THANKS, MOTORHEAD440