72 fj40 turning 35's or 33's (1 Viewer)

[Cruiserhead05]

I have friend fixing up a 72 gj40 real nicely. Onyl thing it will need is a lift. I would love 35's but i want to know how that stock F engine will do with those. i had a 72 early with 31's. What will highway speeds be with 35's and 33's. i know i'd do a 4 inch lift but what would be better 35's or 33's???

 

[Cruiserhead05]

Correct its a 72 FJ40 not gj40. my typing skills are in some serious need of help.

 

[rusmannx]

i have the same modle/year with a four inch skyjacker and it pushes the 33's no sweat. i wouldn't hesitate to go with 35's (i wish i would have), and if you get there and don't like the performance it will give you a nice excuse to throw in soume 4.56's

 

[CruisinGA]

Can always drop in a granny tranny such as SM420 to give you a low enough first gear for 35's, and retain your 4.10's for better highway. The stock 4.10 should be fine for the 33's. A lawn mower engine could push 44's if you wanted it to. All that matters is gearing for trail running. Its mudding where you need horsepower.

 

[LC_Hamma]

A "stock" F turnin' 33's or 35's won't be very happy because of the "stock" 3 speed tranny gearing. You'll be smokin' your clutch on the trail. As mentined above, an SM420 swap will cure that problem. Even on the road, you'll be smellin' clutch smoke leaving stop signs. BTDT!

 

[Landpimp]

A "stock" F turnin' 33's or 35's won't be very happy because of the "stock" 3 speed tranny gearing. You'll be smokin' your clutch on the trail. As mentined above, an SM420 swap will cure that problem. Even on the road, you'll be smellin' clutch smoke leaving stop signs. BTDT!

I agree the 3 speed 1st gear has trouble with 35's even around town. Everything else is fine, just 1st gear isn't low enough. The motor will be fine, 4.11 are fine.

John H

 

[Cruiserhead05]

Ok, 35's may be a little much for the 3-speed. 33's will be fine though wont they, i have now an 82 w/ 33's and its fine. 3.70 gears kinda suck off-road but i dont smell burning clutch.

 

[CruisinGA]

I will be running 33's with the 3 spd temporarily for no more than a month while I get my SM420 conversion together. Then I will be much better off than before, little better on the highway with 33's and much better around town and offroad with a 7:1 first.