Rear Axle Gear Swaps 1968
Short answer: Not from 2.56 to 3.23 or 3.73 with your existing differential case. Per the factory service manual, there were three case types (by ring-gear mounting): one for 2.56/2.78, one for 2.93/3.08/3.23, and one for 3.36/3.55/3.90/4.33 (the 3.90/4.33 used only the 4-pinion locking case).
So from a 2.56 case you can only move within 2.56/2.78. To get 3.23, find a 3.08/3.23 carrier (not uncommon) or a complete axle. The aftermarket (e.g., Richmond) may offer gears that work with your case, but likely not past 3.23. Get a factory service manual (good reprints exist).
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Content last modified: June 13, 2026 at 10:06 am
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