I've got a '79 Bronco with a 460,C6,NP205, and 39" tires and am planning on putting on 44". What I need to know is what to change the gearing too. I was thinking about 5.13's or 4.89's.
The truck is used alot on the street, but also sees some mud and/or sand at least once a month. During the summer it's off road almost every weekend. I'm obviously not building the truck for milage and was just wanted other opinions.
Thanks for the help.

 

I would suggest even lower gears -

Go to any of the large parts suppliers they all have gear tables.
the tables will allow you to target the rpm you want at 60mph as a relation to tire height and rear gear ratio. They also show a "suggested" range I would go on the higher side of the suggested range so that you get better off road performance

Remember you can check your overall ratio by multiplying 1st gear (a A4OD's 1st is 2.71) by the transfer case bw 13 56 is 2.69 or 2.96 forgot which one and the rear end ratio --- I read somewhere that an automatic would want a target in the 40 range for good overall 4wd a rock crawler would want to be closer to the 50 range.

have fun