Easy 14FF swap questions

[Jesse Jaymes]

I may have stumbled onto a free 14 bolt FF. I did some searching in archives here and did not find my answers.

The truck is an 80's Chevy military truck. I will go measure the perches in the AM. I guess I could take about everything that's left on the carcass, which isn't much.

I wanted to know if you can by conversions to adapt 8 lug to 6 lug in order to run the same rims/spares as my front 6 lug 44 ? Can 15" rims be run on the 14FF?

If I must make an offer, I thought these were Gold ? In the archives, most wouldn't offer more than $100. I thought there was more to it than that? I thought these were at least $800 items ?

Rear drive shaft toast and bent, lying in the bed. Lots of surface rust, but it's still 0% humidity NM, and I am sure things could be cleaned up.

I am running OK right now with a 12, but for the right price, if this is a direct replacement, is this a "score" or not ?

Like many others, what else would need to be done other than get the drive shaft squared away ?

 

[Desert Yeti]

Hey man!

There are indeed a bunch of threads about this, but sometimes you've got to try several different search terms and look through a whole bunch of unrelated conversations to get to the relevant stuff. I'm no expert, but since this swap is on my list, I've been reading about it here and there over the last year and here's my gathered info, stirred together with a strong dose of my opinion

14 bolt FF rear axles can be had for anywhere between free (if you're lucky) and $200. We're talking stock, but fully functional, open carrier usually with 3.73's or 4.10's. If it's got better gears or already got a Detroit Locker in it, then the price starts to climb a bit. If they need repairs or are missing brakes, they're on the cheaper end, if they've just been rebuilt, or converted to discs or whatever, they're a bit more, but overall, these axles are not expensive.

The ideal swap candidate is from a 3/4 ton truck (K20) (rather than a 1 ton, K30) because the spring perches don't have to be moved. I'm not positive on this, but I think that 2wd rear ends in the 3/4 and 1 ton trucks are work great too, so when looking for a rear end in a boneyard, look for the C20's and C30's too.

8 lug: Near as I can tell, there's no good way to run 6 lug wheels on a 14 bolt FF rear axle. I'd love to do this as I have some really nice 6 lug aluminum beadlocks. There was an outfit that used to make conversion kits for it, but they're no longer made and and the kit was more expensive than converting the front axle to 8 lug and buying 4 new wheels anyway. Best bet is just to go 8 lug all the way around.

You can get the parts to turn your D44 front into an 8 lug from a lot of different 3/4 ton models. Most of the 70's K20's had 8 lug D44s in front, just get the parts you need to convert your existing front axle to 8 lug. By the way, 8 lug 10 bolt front parts from the "C" of the axle housing outward are interchangable (as long as you swap everything), and there are literally hundreds and hundreds of 8 lug 10 bolts in junk yards everywhere (especially here in the west where they're not rusted away). If this truck you're looking at pulling the rear out of has an 8 lug front, pull that outers from it and and just convert your truck to 8 lug.

As for the swap, if it's a 1 ton truck, you've got to move the spring perches a bit and move the shock mounts. If it's a 3/4 ton axle, you only need to deal with the shock mounts. Make sure the gearing matches your front axle, or plan to regear it as part of the project. You'll need to do something about a driveline, using a conversion U-joint (a 1310/1350 combo...I think?) is probably the easiest way to deal with it, at least for the short term. Buy some 8 lug wheels, selling your 6 lug wheels to recoup some of the cost, and you're set!

If you can weld and have a friend to help move that heavy sucker around, it's really a pretty cheap/easy project. If you pay someone to do the fab work, and/or you re-gear and/or add a locker and/or go with a custom driveline, etc, etc, etc, it can add up kinda quickly, so just be aware.

 

[fryed_1]

If it's actually from a military CUCV, then it's 4.56 geared with a detroit and a good find for free, so long as it's functional.

Far as swapping the front over to 8-lug, just need hubs, rotors and caliper backing plates and all should be good. Probably less than $250 easy even if you buy everything brand new. Less than $100 easy if you find them in good shape used.


Does the carcass have a front axle in it?

 

[AJMBLAZER]

The military 14FF has the 1 ton spring perch spacing, shock mounts, and BIG drum brakes so all of those will have to be addressed to put it into a half ton.

The rear brakes on it CAN'T be used with a 15" rim but at least that gives you a reason for rear discs.

Cutting and welding fixes the spring and shock mount issues.

If it's just sitting there offer them what you feel it's worth. If it's in good shape and doesn't need any fixing keep in mind that the Detroit and 4.56 gears alone would go for over $500 new. Actually probably over $600.

 

[BulldogK5]

How did this turn out?

 

[USSkoval]

Just to clarify, the 14ff from a K30 OR C30 both have the same perch spacing and shock mounts. The C30 axle is not the same as a K20.