Want to swap the 10 bolt rear with 4:88's to a 14 bolt which is best?

[Z71rider88]

I have a 1994 k1500 lifted i do towing and have 35's and a lift i want to go with the strongest rearend i can put in there so i can run on highways a little better and tow which 14 bolt is best to use and what gearing also drums or disc brakes or does it matter? and yes i know im rambling sorry

 

[magimerlin]

Well to keep 6 lug you are stuck with a 14b semifloat. A full float 14b is 8lug only unless you can find the unicorn I hear about once in a great while of a 6lug 14b full float.

As far as disc or drum...
the 14b drum is huge, meaning it'll fill a rim real easy.. 16" plus rim minimum is required. But will work fine with your brake system with no issue.
If you do disc.. you will likely need a new master comparable for 4 wheel disc or a separate adjustable proportioning valve to adjust the rear.

I believe both ff and sf axles are available in disc. Either way though. Make sure since you are 4x4 that you get one outta a 4x4. The width of the axle is differant between 4x4 and 2wd.

As far as getting with 35's... depends if you have an auto or a stick. Since most are auto, I'll go with that. With 35's, 4.88's should be close to stock as most k1500's are either 3.42 or 3.73... if you want more grunt for get up and go the next hear is a 5.13 but I do not believe the front axle carrier can handle that. I wanna say if I remember right 4.88 was the steepest front gear set that'll fit.

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[Z71rider88]

Ya I have a Auto but those 4.88 gears are not very highway friendly so I want something that can handle towing and highway driving I plan on selling the 10 bolt setup with 4.88 gears she gets up and moves pretty quick just don’t think I can run ge highway that good

 

[magimerlin]

Ya I have a Auto but those 4.88 gears are not very highway friendly so I want something that can handle towing and highway driving I plan on selling the 10 bolt setup with 4.88 gears she gets up and moves pretty quick just don’t think I can run ge highway that good

If the 4.88 feels to high I'd go with a 4.56 ratio for the simple fact you still wanna be able to tow. You could go 4.10's but I feel they may not be steep enough for 35's and towing when in drive(gear shift on 3) as you never want to tow in overdrive. That's coming from past experiences both on and off road and with many differant vehicles.

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[slowburb]

14 bolt semi-floater has a 9.5" ring gear. The brakes would be dictated by the build of the truck it came from. I have a JB6 Suburban, and I installed a JB6 coded 14b from a heavy half ton. This means 6 lug hubs to match my half ton Suburban. I'm running 4.56:1 gearsets (NOT 4:56), and 33" tires. This calculates out to a little bit hotter than a factory truck with 4.10:1 gears. I turn around 2700 RPM at 80 mph. I'd say this is equivalent to factory tires and 4.30 gears. This is a hot street or offroad setup, or an aggressive towing setup, not highway friendly at all.

4.56:1 gears and 35's is just about the same as factory tires and 4.10 gears. 4.88's and 35's would make for a lot of RPM on the highway.

 

[84cj]

Love the 14b SF rear brakes. Much improvement over the 10 bolt brakes.

 

[Z71rider88]

When I swap to the 14 bolt will I need to change my master cylinder out to handle the bigger axle/brakes?

 

[slowburb]

"Bigger brakes" is a misnomer of sorts. It is completely dependent on the brake setup of the donor vehicle, and the brake setup on your truck, as I already stated above. Let's use my truck as an example again. My truck is brake option JB6, and the axle I swapped in is JB6. This means the brakes are the same size, so no other changes were necessary; just connect, bleed, and go. This would be the ideal path for you to follow.