3.07 gears

[dmulhall]

I'm looking to do a cherokee rearend swap and locally I can only find cherokee with a 5 speed tranny that would make the rear ends  be 3.07 gearing...

I have a 50 b2b with a industrial 251 and three speed...I'm thinking the 251 should be big enough to handle the 3.07 but I've been reading that guys are alot happier with the 3.55

I would appreciate any thoughts or experience...I know the braking conversation with drum brakes already

Thanks

[55 Fargo]

3.07, with a 250, well you have a bit more grunt than a 218, so it  might not be too bad.

Hills, strong winds, acceleration in 3rd gear until you hit the RPM powerband, might be a concern.

Reg Evans has a similar set-up, and he likes it.....

I have 3.23, and like it, but could use a bit more power, my engine is a 228, you won't have to worry about Overdrive.or tall tires

[NiftyFifty]

3:07 is way to low, I have 3:55 with a slightly improved 251 and on a really windy day, or fighting a big hill, there no way 5th gear is useful because the engine rpm is too low.  I'm planning a 3:73 swap in the future, just to make it a but more friendly to use that OD, but if your more happy at 55 or maybe 60 mph you could likely stick with a 3:55, but you don't have enough hp at low rpm for 3:07

[Jeff Balazs]

Way too tall in my opinion. Find a 3.73 they made lots of Cherokees with that ratio.

Jeff

[dmulhall]

Thanks guys

[Plymouthy Adams]

lot of the 4wd units were 3.73 as standard ratio.....do not rule out an early Dakota 4x4 either...

[William Davey]

16 hours ago, dmulhall said:

I'm looking to do a cherokee rearend swap and locally I can only find cherokee with a 5 speed tranny that would make the rear ends  be 3.07 gearing...

I have a 50 b2b with a industrial 251 and three speed...I'm thinking the 251 should be big enough to handle the 3.07 but I've been reading that guys are alot happier with the 3.55

I would appreciate any thoughts or experience...I know the braking conversation with drum brakes already

Thanks

My truck is a little newer and the 259 V-8 may have a little more power/torque than your 251, but here's my opinion. Years ago I bought a 1st generation Dakota rear axle with 3:55 ratio (currently truck has stock 4:10). I have never installed it because....... I usually drive on secondary roads where 55 mph speed is fine. Around town I can take most low speed turns in 2nd gear without trying to downshift to the non-syncro 1st gear (PITA). Soooooo. IMO, for my driving and use the stock gearing is better and more flexible. Future plans include maybe someday installing an A833 OD transmission with the adapter from the Aok boys which solves the non-syncro problem, but creates a new dilemma. Maybe the 3:55's are too low for the OD on the A833.  So while I try to figure out what in hell I'm doing I drive and enjoy it as is. 

[59bisquik]

I know 3.07 is a fairly steep ratio, but just throwing this out there... take your tire size into consideration also.

I started out with 4.11's and 7.00-15 tires that were close to 30" tall. I swapped in the 3.73's and it was a nice driver. After installing my new 225/60/17's which are 2" shorter, it's equivalent to 4.11's again. 

So consider that also when picking a gear ratio.

[55 Fargo]

yes tire size can alter your final drive ratio, but unless these trucks are lowered, smaller tires don't look that great.

Reg Evans has about the same gears in his truck with a 250 engine, he loves it, Reg lives in hilly terrain does he not?

Interesting these higher gear ratios would or might work okay with the early NWC T5, there 1st gear ratio is quite low.

The 3.07, 3.23 and even 3.55 might not be the greatest choice with the New Process A 833 OD trans, gear spread is as follows,

1st 3.09, 2nd 1.67, 3rd 1.0, 4th OD .73.

Having another 30-40 hp would make higher gear choices a lot more liveable..

 

 

[Reg Evans]

On ‎10‎/‎7‎/‎2016 at 7:53 PM, Rockwood said:

yes tire size can alter your final drive ratio, but unless these trucks are lowered, smaller tires don't look that great.

Reg Evans has about the same gears in his truck with a 250 engine, he loves it, Reg lives in hilly terrain does he not?

Interesting these higher gear ratios would or might work okay with the early NWC T5, there 1st gear ratio is quite low.

The 3.07, 3.23 and even 3.55 might not be the greatest choice with the New Process A 833 OD trans, gear spread is as follows,

1st 3.09, 2nd 1.67, 3rd 1.0, 4th OD .73.

Having another 30-40 hp would make higher gear choices a lot more liveable.

Yes, I have a 50 Chrysler 251 in my 52 1/2 ton. The head was shaved .050 and the rest is stock.  The rear end is a Ford 3.0 to 1 from a 65 T-bird and the trans is the stock 4 speed.  I'm very happy with this setup.  Before this truck I had a 47 Dodge 1/2 with a 241,3 on the floor, and a 65 Ford Wagon 3.0 to 1 ratio. I was happy with it's performance too.  Both of these trucks were used in my construction company and hauled lumber and supplies to the job sites all the time.

 

 

Edited October 19, 2016 by Reg Evans

[48Dodger]

Yeah!! I have a 1997 Thunderbird Independent Rear Suspension it works great.....but...uh...I have a... 500hp stump pulling, thingy...V8 that...

ok.....not relevant to your build.......I was just enjoying the thread, and well,  I felt left out. 

carry on.

 

48D

[pflaming]

Tim, I have a 87 T Bird rear suspension, axles, et. al. It is a complete unit, held on by four bolts. The ratio is 3:73. Maybe put that under my suburban, the independent suspension would give that car a great ride.

 

Edited May 27, 2017 by pflaming
Delete