14bolt FF size vs 10bolt

[BryanS]

I’m swapping a 14bolt FF into a k5

Truck has a 4”lift and currently the slip yoke sits out pretty far. Drive shaft looks like it is 2-3 inches too short.

My question is the new diff is bigger. Does that mean the yoke on the diff is maybe 2 or three inches longer and then like magic my drive shaft will be just the right size now?

I’ll need a special joint that would connect to he 1/2 tan shaft to the 3/4 ton axle that I’m assuming someone makes

 

[Bextreme04]

I’m swapping a 14bolt FF into a k5

Truck has a 4”lift and currently the slip yoke sits out pretty far. Drive shaft looks like it is 2-3 inches too short.

My question is the new diff is bigger. Does that mean the yoke on the diff is maybe 2 or three inches longer and then like magic my drive shaft will be just the right size now?

I’ll need a special joint that would connect to he 1/2 tan shaft to the 3/4 ton axle that I’m assuming someone makes

Yes, the 14BFF yoke is(I think) about 2-3" longer than a 10 bolt one. You will want to check driveline angles also before you bolt everything together.

 

[Zelph]

NP 208 transfer case?
Weld in new spring perches with the proper pinion angle.
Measure and order a new driveshaft from a vendor of your choice.

You must be registered for see images attach

You must be registered for see images attach

 

[BryanS]

NP 208 transfer case?
Invest in SYE kit.
Weld in new spring perches with the proper pinion angle.
Measure and order a new driveshaft from a vendor of your choice.

You must be registered for see images attach

You must be registered for see images attach

I think it’s NV261

 

[Zelph]

What side is your front driveshaft on? Or the front axle differential?

 

[Old Guy Bill]

I think it’s NV261

Are you sure?
I believe the 261 is a drivers side drop

 

[Zelph]

I’m thinking he has a 208.

If not, we need to figure out what front axle he has.

 

[BryanS]

I may have seen the wrong numbers

Is this the tag I should be looking at?

The front shaft is on the correct (passenger) side

Here are a couple pictures of the case

Thank you guys

 

[bucket]

The 208 was used from '81 to '88. Then the 241 was used after that. No 261 in these trucks.

Yes, the 14 bolt diff is bigger, but the yoke is rather close to the center section for it's size. Your driveshaft will fit roughly the same after the swap.

The conversion u-jount you need is Precision #447. Unless parts have been swapped around in the past, of course.

 

[Zelph]

That there is a 208.

I wouldn’t buy any u joints on assumptions. Get a set of calipers and measure what you have and buy accordingly.

We’ve all seen weird and strange things on these trucks that typically get blamed on a po, but the factory did some odd stuff too.

 

[nvrenuf]

The “261” on the bottom of that tag denotes the low range gear ratio - 2.61:1.

 

[BryanS]

The “261” on the bottom of that tag denotes the low range gear ratio - 2.61:1.

Got it. That makes perfect sense