I can't say right here. Take it to PM's. I will get in trouble for breaking forum rules since this is the Garage and not the For Sale forum.
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The carrier split for FF 14 bolts is 4.10 and down and 4.56 and up.
That means that 3.21, 3.42, 3.73 and 4.10 FF 14 bolt gears all use one carrier, while anything 4.56 and deeper uses a different carrier.
Because most 14 bolts start with 4.10 or higher (numerically lower) gears, and most people re-gearing them want deeper gears, the aftermarket came up with the concept of "thick" gears. The thick gears will fit a 4.10 and down carrier (most common by far) but allow you to run 4.56 or deeper gears without changing the carrier. The "thick" 14 bolt gears are the vast majority available for anything 4.56 and deeper.
