Yes thanks as wasnt 100% if was that exactly and dr diff also said:
Turn the housing UPSIDE DOWN on jack stands.
2. Place a floor jack under the pinion. Use an angle finder to point the pinion 5 degrees downward (toward the ground).
3. Level the perches at 43" and weld. This will result in a 2 degree negative pinion angle when the housing is installed in a stock A-body with my 1/2" offset spring hanger/shackle kit"