More questions about 14bFF/Dana44 swap

[omgang]

I have a 76 K5. It has the stock 12b rear and a Dana44 front (I think) with 3.08 gears. I've been running 33x12.5's for quite some time (rear tires are about shot so 25,000 miles or so) with a very stout motor but am now wanting to go up to 35x12.5's. I've been reading a bunch of threads here about swapping in a 14bFF and Dana44 from a 3/4 ton but still have a few questions.

I primarily use the truck for hunting. No mudding or crawling etc. I'd definitely like the advantage of taller gears particularly when I move up to 35" tires. I don't plan on going bigger than 35's because I don't want to lift it any more. Is the 12b, Dana44 combo I have now adequate, assuming I re-gear those, or am I just asking for trouble? From what I've read it seems like the 14b/Dana44 combo is quite a bit stronger than a 10b/10b setup but I didn't see anything saying it was way better than a 12b/Dana44 combo.

For a swap into a '76, what else will I need (aside from the 3/4 ton axles)? Am I correct in my understanding that if I get donor axles from a 3/4 ton I won't have to relocate spring perches, i.e. both axles will bolt right in? Will I be able to re-use existing rear drive shaft (brand new with the lift kit)? Front drive shaft (brand new two years ago)? Will I need special u-joints? I've already got extended steel brake lines; will I have to change those out? I've read about changing out brake backing plates on the 14b but does that only apply to newer K5's?

If I can pick up a set of 3/4 ton axles for $300 and go through them replacing seals, bearings, brake components, u-joints, ect. and get a set of 8-lug wheels am I going to be at roughly the same amount of money as a gear swap in my current set up? Or is the axle swap going to be less money?

I'm not trying to be cheap about this but if I really don't need the 3/4 axles for my rig it's a lot less work to just re-gear the existing setup and buy new tires. Please give me your honest opinion.
Thanks,
OM Gang

 

[raymos]

when i had my d44/12b i never had any problems with them (besides lack of maintnence) and i wasnt easy on them with 35's.

the only thing i can think of that you would need is a conversion u joint for the rear end. every thing else should bolt in.

obviously both fronts are d44s so it is not gonna be any stronger, but the rear 14bff is stronger than the 12b. and it is a full floater so if you do break a shaft your wheel will still be attached to your truck.

what gear ratio are you looking for? you could easly find 3/4 tons with 4.10. and as far as a gear swap, when i put 4.56 and a detroit locker in my 3/4 tons the parts alone cost me about $900

hope some of this helps

 

[4X4HIGH]

I would swap in a 14ff in the rear (you can find plenty with 4.10 gears) then do a gear swap up front along with the 8 lug conversion. This would probably be the cheapest and strongest way to go. If you can find a front 8 lug axle with 4.10 gears cheap enough that would save you some coin as well.

 

[omgang]

Thanks for the quick responses. I have an opportunity to get a 14bff/Dana44 set with 4.10 gears for $275. I'll still need to get u-joints, u-bolts, seals, bearings, brakes, 8 lug wheels but it sounds like I may be money ahead, and have a stronger rear to boot, by going with this setup (vs. ~$1000 for a gear swap on my existing components).

So no worries on brake backing plates then?
Thanks,
OM Gang

 

[throttleissues]

No need to change anything around on the backing plates. If the 14ff uses the same park brake setup, you should be able to hook it all up easy. Since it's a set with a D44, it'll probably be the same as your 12b cables.

 

[Desert Yeti]

Pretty much what's already been said...

If you can get a good deal on 3/4 ton axles that already have the gears you want in good working order, it may actually end up significantly cheaper to swap axles and buy new wheels than to regear your 1/2 axles. Part of it depends on how fancy your wheels are too... if you'll be happy with some plain ol' black or white steel wagon wheels, they can be had cheaply...even brand new.

Sounds to me like you don't NEED the heavier axles though, so I suggest you work up a real bottom line for all parts and labor for each option and go where the savings takes you!

 

[omgang]

Pretty much what's already been said...

If you can get a good deal on 3/4 ton axles that already have the gears you want in good working order, it may actually end up significantly cheaper to swap axles and buy new wheels than to regear your 1/2 axles. Part of it depends on how fancy your wheels are too... if you'll be happy with some plain ol' black or white steel wagon wheels, they can be had cheaply...even brand new.

Sounds to me like you don't NEED the heavier axles though, so I suggest you work up a real bottom line for all parts and labor for each option and go where the savings takes you!

Exactly. I'm in the process of working up costs for both options right now. I need to get a local quote for a gear swap since I don't want to try it myself but I'm anticipating somewhere around $1000 total for both axles. My Blazer is camo and has stock rims on it now; I'm not looking for anything fancy in wheels and I'll be buying new 35" tires either way.

Thanks for the response.
OM Gang

 

[4X4HIGH]

If you go with the upgraded axles make sure you buy 16" wheels or larger but i would skip 16.5" wheels all together.

 

[scrappyk5]

dana 44 front 8 lug will bolt right up including ujoint. 16.5" rims unless you want to grind calipers for 15" rims.

14bff 3/4 ton will bolt right up. will need to change u joint to accomodate the pinion on the 14bff. I think the 348 conversion joint is the one you need. plus ubolts and spring plates. brake lines bolt right up emergancy cables might not.

4:10 gears with 35's is fine but if you have a th350 you will be high revving on the highway
( footnote , with my th350, I am running about 2500 rpms with 37s at 65mph. my gears are 3:73s

 

[Desert Yeti]

Admittedly, it depends on the tire and wheel combo you want to run, the stance you like, and what you plan to use it for, but you CAN do 15 inch wheels on that 8 lug front with no grinding if you just run 15x8's with 2.5 inch backspacing.

Worked like a dream on my rig. I had a screaming deal on some 37's that took a 15, so I had incentive to make it work and I love it! The stance is really nice although probably wouldn't want to go wider than 8 inch with that backspacing or it'll start to look goofy and add stress to the ball joints.

If you're going to buy new wheels AND tires anyway, 17's are probably your best bet.

 

[omgang]

Thanks for all the replies. I've been shopping for, and wondering about, wheels. Can I use stock rims from a 3/4 ton truck or is this a bad idea? If so, what years (I see adds for '99 and up, etc.). For 35 x 12.5 what is the best width and backspacing (I've got a 4 inch lift now and am thinking of adding a 1 inch body lift as well)? Wheels are looking to be more expensive than I thought but I also got a quote locally to have gears installed in my existing axles, $1200, so the axle swap is looking better.

Regarding the highway rpm - I have wondered about that but the motor I built likes rpm and gets ****ty fuel mileage now with 3.08 gears. I really feels best at speeds over 75-80 mph and my truck has no business going much faster than that. It's not a daily driver so I think I'll be OK.

OM Gang

 

[omgang]

If you go with the upgraded axles make sure you buy 16" wheels or larger but i would skip 16.5" wheels all together.

Skip 16.5" because of ???? Tire availability? Or other reasons?

Thanks,
OM Gang

 

[SkulzNBonz]

Skip 16.5" because of ???? Tire availability? Or other reasons?

Thanks,
OM Gang

Tire/wheel availability and cost as well as the tire's unexplicable desire to separate themselves from the rim at anything less than street pressure.

John

 

[Desert Yeti]

Thanks for all the replies. I've been shopping for, and wondering about, wheels. Can I use stock rims from a 3/4 ton truck or is this a bad idea? If so, what years (I see adds for '99 and up, etc.). For 35 x 12.5 what is the best width and backspacing (I've got a 4 inch lift now and am thinking of adding a 1 inch body lift as well)?

Older stock 3/4 ton wheels are going to be 16.5 inchers. They lack a safety "ridge" on the inside of the wheel that keeps the bead seated. Newer 3/4 ton stuff is going to be either 16 (more limited tire options and becoming more limited by the day as wheels trend larger) or 17s. If you're buying new wheels for 8 lug axles and don't have some compelling reason to do otherwise, get 17's, IMO.

If you're going to wheel this thing, I'd put 12.5 inch wide tires on an 8 inch wide rim. Keeps the beads in place better and protects the wheel from damage. As for backspacing, depends on clearance issues really. You probably one to go as close to zero offset (backspacing that equals half the rim width) as possible while still getting the clearance you need. Most of these older trucks like a slightly shallower backspacing than the newer trucks... about 4 inches is pretty standard, although (as mentioned earlier) I went with only 2.5 to clear the 8 lug brakes with 15 inch wheels.

 

[omgang]

Thanks for the info. I was wondering about rim width. While I was Googling for wheels/tires I found a thread on another forum regarding 8 vs. 10 inch rim width. On that thread a few of the posters were very in favor of the wider rim. I've been running 33x12.5 on stock rally rims for a full tire lifetime and have had no problems so I was kinda hoping/guessing 35x12.5 on would be just fine.

Trying to find used wheels locally (Montana) is probably unrealistic so I've been checking out on-line sources for new. Seems about the best deal I can hope for is $120/each for new aluminum rims (with free shipping). That puts me at $480 for wheels and $275 for axles. Haven't priced u-bolts, u-joints and anything else I might need but figure another $50 - $100. So ~$800-$850 for axles vs. ~$1200 for gears. Still should be money ahead with the new axles and rims route.

BTW - are my current 12-bolt, dana-44 and rally rims worth anything at all?

Thanks,
OM Gang

 

[omgang]

Why is it tires for a 17" rim cost more than tires for a 15" rim? There's less material in the tire for the larger rim. A quick comparison of something like Cooper Discover STT shows 35x12.5-17 cost about $160 more per set than 35x12.5-15. Bummer that.
OM Gang