Freshly gone thru 4.56 Chevy 55-64 differential. Open drive but in a posi case. Posi cases are different inside for posi clearance. A factory posi could be dropped in without mods. Original factory marked 1968 GM gears. The carrier had a problem in an earlier life. A pinion got into it. Not these gears. Gears and bearings look great. It was set up using factory manual specs. Pinion torque is 20 in-lbs to factory 15-25. Backlash measured .007 to spec of 005-.008. Has new seal installed. Case has never been painted or blasted. The yellow paint is factory. Some light rust on outside surface but to be expected after 62 years unpainted. Casting date Dec 62. No rust inside. View attachment 6367148 View attachment 6367152 View attachment 6367153
The Jalopy Journal
