There is no "standard" pinion shim thickness. The whole purpose of shimming gears is to correct for manufacturing tolerances that add up and build in errors in tooth contact patterns. OEM pinion gears had depth adjustment information electro-penciled on the back end of the gear, which might be "(+4)"- - - -"(-3)", etc., which indicates the distance in thousandths of an inch from the centerline of the ring gear the pinion gear needs to be positioned. If the markings on the original gearset can still be inspected, a WAG can be made about how to alter the shim pack. Final tooth contact patterns MUST be checked and adjusted as required, using some type of indicator dye such as Prussian Blue or white lead. Somehow, I think it's impossible to get a backlash of nearly 3/4" "(.7)" ?????? Maybe that was intended to be ".070"? Yes, decimal points and place-holder zeros do matter! There's no substitute for an extensive amount of experience in setting up rear ends, except maybe blind luck!
Jerry
