there were three ratios available, 4.10, 4.56 and 4.88. none were "standard" there should be a label on the hood that will tell you what ratio came with the truck, also there is a tag in the diff cover.

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'01 P1500, Blown/Inj BAE,/Veney ,Bruno/CS2,Dana 60
'01 Dodge 3500 S Cummins Auto, Fresh air kit, 4" Exhaust,
'05 Dodge Magnum R/T - Too Much to list
'60 Willys CJ5
'01 International LPX - Project,DT466, Allison
'64 Plymouth Valiant, Inj 528 Hemi, 2spd