86 toyota pickup 22re with 235/75r15 tires, I am thinking of dropping a v6 in my truck for perfomance and I know I need to change the diffs but I was wondering was size gears to I need to put in to get better gas milage on highway and still have performance off roading

 

Are you going automatic or manual? The 3.0 is not as user friendly as the 22RE as I speak from experience. I have both and both are not powerful engines and if you go through the swap ($$+time) you may not be thrilled. I pull hills (Paved roads) at similar speeds. In my opinion the 22RE is an easier engine to work on. The 22RE has better fuel efficiency and on the trail in 4 wheel dive my 22RE is just as capable. Just my opinion, as far as gearing, do you plan on keeping stock tires? That will be a major factor on selecting the correct gear ratio.

 

Probably best to pull up Marlin Crawlers site and use the gear calculator. There is also another site that has a comprehensive gear calculator. I'm too lazy to do the searching for you. This topic is also covered in the FAQs.

Good to consider intended use of rig. For the time and money if you want a locker it is the time to do it. You'll need to regear both front and rear diffs or find stock diffs geared closer to ratio you decide on. Be careful looking at used diffs as setting up toyota diffs is easy to flub up, trust me I learned the hard way. Check out gearinstall.com Zuk is a toyota diff guru!!!!