gear ratios........????

mike4089

im finishing up my 360 swap into my 83 cj-7....it have the stock 2.73 gear ratio and i think down the road id like to change that.....i want to change to a ratio that i can still drive down the highway with comftorable and take off road occasionally.....and recomendation???.......i will eventually be running 35" tires on the jeep

tufcj

You're going to need to be in the 4's. with 35" tires, 4.10s would give you a good cruise, but it still might lack power to pass or climb hills. 4.56s would give you back the power, but your cruise RPM would be higher, and mileage may suffer a bit.

Here's a link to a calculator. There are others out there.
http://www.dirtroadmagazine.com/gears.htm

Your 83 CJ should have an AMC20 rear and Dana30 front (unless you've changed them). Bad news is both carriers have to be changed when you have 2.73s. Time to think about some type of lockers or posis, and definitely consider 1 piece axle shafts for the 20. That way you'll only have to pay for installation/setup once. It's definitely not a do-it-yourself if you don't know the procedures and have the tools.

Bob
tufcj

76-cj7

If 4.10s are still a bit high and 4.56's are a bit low....then go with 4.27's

tufcj

The trouble is that 4.27 is made for the Dana30 and 44, but not for the AMC20. I run 4.27s right now (I have 44s in both ends). When I lived in Colorado, I wished I had a little more gear when climbing the mountain passes. Down on power because of altitude and 6-8% grades. That was with 35s. I now have 37s on the CJ. I have 4.88s waiting for install (and a 60 rear as well). Bob tufcj

76-cj7

Yea.....i forgot the about the M20 for a second......but i've got a dana 44 one piece shafts and narrow track??? with 4.27's in it......in fact i have another one with 3.73's and i want rid of them.....taking up space.

zero cool

I wrote a gear ratio calculator so you can do side by side comparisons of different ratios and see what would work best when changing tire sizes.

http://www.grimmjeeper.com/gears.html