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popeye
Well-Known Member
Lifetime Member
4.88 was the stock ratio in the mid 2000s f450-550s I believe, is that what the rear is sitting with now? have you ran the gear ratio through any calculators to see rpms and speeds of each gear?4.88 is the lowest they have for the rear so 4.88. Ford went to a 37 spline pinion that year so not many options yet.
If not this is a handy site that will help
http://www.grimmjeeper.com/gears.html
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