Planning out my new course of action for my build(waaay different direction). I`m currently researching how to make this all come together, but the plan as of now is:
`69 240ci six cylinder(maybe upgrade to a 300 later)
NP435(not sure on clutch linkage)
Manual shift BW1356
1/2 ton axles(D44/9in) on leaf springs
35" tires

This truck will see trails, and minor mud(no 4ft deep pits for me), along with some street and hauling duties. Nothing major like towing a car twice a week or anything, just regular truck stuff. I think 35`s are a good compromise for the intended use.

What I am unsure of is the gear ratio in the axles. I have never had a rig with a low first gear like the 435. 3.54s would be easy to find in the axles already, but I don`t want to be unhappy with my gear ratio.

So, anybody who has or had a rig similar, give me some opinions on what gear ratio you like.

Thanks,

 

with 35's Personally id go with minimum of 4.11's.... while you got that low first gear you wont always be in first.

 

True, but offroad I`m very near always in low range. And with the 1356`s 2.69 low range it would still be pretty good.

Played with the numbers more tonight, thinking 3.73`s would be a good compromise. Not sure how easy it would be to find/get axles with 3.73`s in them though.

 

See there now I have confused opinions for advice. I thought he was asking for advice. But looking back I see he did indeed ask for opinions. Now he's going to tell us why he has a different opinion.

 

With that tinny little engine, the highest gear I'd go would be 4.10. Lowest would be 5.13.


So with my experiance, I'd pick 5.13.

 

Eeeeeh.....


A 240/300 wont rev much past 4000rpm and makes most of their power below 2500.

I have 3.50 gears and 33s on my 79 150 with a fairly hopped up 300 and a 435. 1st is still useless and i get good mileage(15-16mpg with a 4bbl)while keeping the ability to pull hell off the hinges with that 6.xx:1 first gear

All this being said id go with 3.93 or 4.10s for 35s. I would not regear the 44 below the carrier break

 

Sorry, just thinking out loud. I ran a bunch of calculations on the gear ratio, but I do realize that numbers don`t always equal real life.

Carry on, thanks to those that have posted(hav24wheel, 77mud and alpha/omega).

 

idk that id go 5.13's with something thats gonna see more hwy time than deep nasty mud, I do however run 5.13's in the race truck but its pretty much for mud only. Id go minimum of 4.11's mainly because you mentioned towing and going down the hwy towing you dont wanna kill it cause its geared wayyyyyyyy to 'high'

 

RPM= (Gear ratio x MPH x 336) / Tire Dieameter

If your gonna run on the highway more I would assume your gonna want to run at about 2000 RPM

2000 = (GR x 55 x 336) / 35

GR=(2000 x 35) / 55 x 336

GR= 3.79

So to run at 2000 RPM on the highway you need 3.79 Gears. But that will give you the best on road performance (IMO). If your looking for power on the trails and in the mud Your obviously gonna want to run lower.

For reference here is what your setup will give you running lower gears on the highway :

Running 4.10's you'll run 2165 RPMs @55MPH
4.56's You'll run 2408 RPMs @55
and 5.13 you'll run 2708 PRMs @55

 

id go 4.10 at most 4.56 for somethin that will be on the road with 35s

 

I have 4.56's and a 35's on my DD. Seems about right to me

 

Does your truck have a straight six in it?

 

302/np435. If you do a lot of highway driving I would go with 4.10's

 

honestly power wise i dont thing there's alot of difference between the 300 I6 and the 302, i do know the 96 300 i had would out run my buddy's 95 with a 302

 

Hell idk, I think a 302 will out do a I6 any day of the week. Most people just don't rev the 302 up high enough to reach its full potential.