i have a 76 f250 highboy. supposed 2 have dana 60s front 4:11 rear 4:10. rear axel came outta a bronco hadta move spring purches in 3.5 inches( got behind seat tank frame 34 inchs) no id tag. its got 60 stamped on it nd c-30255 stamed also. i wanna know gear ratio. spedo doesnt work. found a calculator on line to determine speed but need to no gears 4 every thing. np2o5 1.96:1 t case. 33x12.50x16.5 tires(need a set , bigger,if ne one has ne) that measue 31. nd trans tag nums d3ta7003dc fl112 3 17 76 435.if u no ne thing bout the date codes i dont ad up... d means 70. 3 means 3. t means truck. a means axle. but the date says 76. wtf is goin on. i know the truck will only do 78 in 3rd but the slowest speed i cld find on calck says 95 nd its jst not gonna happen in this truck evan wit the c5ae 289 hi po wit 600 cfm edelbrock 4v... if ne of this makes sence cld u help me out...