So I got a 76 f250 high boy and I’m trying to figure out what the best axles are for the build I’m trying to make. The trucks getting a 521 stroked 460 that’s going to make somewhere between 550 to 700 hp and I’m just wondering should I swap some superduty axles or should I rebuild the stock ones? Or maybe I do a different kind of axle. Just looking for some advice.

 

I think the late '70's F350 pickups came with a single rear wheel drive Dana 70 axle assembly.
The F250 high boy probably came with a single rear wheel Dana 70. A Dana 70 should be sufficient.

 

So what should you do for the front? It’s a 4x4

 

Info from the FTE archives: "Highboy front axles were an 8-lug low-pinion Dana 44 (1967-1977.5), 8-lug low-pinion Dana 44HD (1969-1975), or 8-lug low-pinion Dana 60 (1973-1975, Crew Cab Highboys only). There were no high-pinion front axles in Highboys, although high-pinion front axles are preferable to low-pinion front axles. The Highboy front axles were a closed-knuckle design from 1967-1975, and open-knuckle design in 1976-1977.5. The open-knuckle design is preferable. Many Highboy owners replace their low-pinion front axles with a high pinion 1977.5-1979 Dana 44, or better yet, the 1979 high-pinion HD Dana 60 with 35-spline inner shafts and 30-spline outer shafts.

Rear axles were an 8-lug full-floating Dana 60 with 16 splines (1967-1975) or 30 splines (1967-1977.5), but both were the same 1-5/16" diameter. It is common for those with the 16-spline Dana 60's to replace them with a Dana 70, GM 10.5" 14-bolt, or other rear-end."

So that being said, if you have the common older low pinion axle Dana 44, IMO ditch it because there is NO aftermarket support, so getting things like up graded chromoly axles shafts is pretty much out of the question. I have a low pinion 76 Dana 44 in my 76 Bronco crawler and can not even find stock replacement front axle shafts. I am switching it over to a full width high pinion properly built 79 Bronco Dana 44. All sort of upgrade parts are available for that axle.

Rear Dana 60 can be built to support that HP, I would think a Dana 44 could be depending on what you are using the truck for. A 77.5/79 Dana 60 front axle would/could be built too support the HP better. But just finding that axle they can be like $1500 to $2500 these days. What are you plans with the truck, race, mud race, off road?

The newer and just as heavy duty as a older Dana 60 (if not even stronger) SD axles can be found WAY cheaper as a set, versus ONE 78/79 Dana 60. Battle Born Brakes sell kits to put the SD axles under your truck.

https://www.battlebornbrakes.com/sup...le-conversions

 

It's troubling that the axles are peoples' primary concern.

First and foremost, find new yokes for the transmission, transfer case, and the driveshafts/axles that aren't 1310/1330s. Anything from the 70's is going to be way too small/weak. Just because it's a "highboy" (what a stupid term) doesn't mean it's any stronger or any more heavy duty. It actually means you have two more tiny u-joints to worry about that "married box" pickups don't.

1410 minimum if your're using any of that power.

 

I put a late model gm 14 bolt under the truck I picked up for a song with a locker on it had to move the spring perches (add them back in this case) I believe the earlier ones are more or less drop in though if I remember right its 34 center to center tilted 15 degrees forward (pinion slightly up with the perches level) however check for yourself first

The factory rear sucks so something bigger is definitely called for

With the front I went with the 79 dana 60 I also got for a song also with a locker 35 spline outers and some other aftermarket ****ery with the kingpins and steering I still need to sort out

The superduty axles seemed like a good choice but only if you converted to coils which was more work than I wanted to do

 

What is the intended use? High or low traction? (dry rocks or mud or ?)

If you want to keep the front leaves, the front axle kinda has to be what you have or a early D60 with a longer short side tube for spring perch spacing. Expensive and not common.

Next step is 80s-90s KP or BJ D60, reverse rotation. Spring pads farther apart. diff is too far left for leaves. 8x6.5 bolt pattern. Have to fab. or 99-04 SD leaf axle, better brakes, 8x170

05+ SD have larger C's to fit larger knuckle u-joints. Beefer stub shafts. Radius arm mounts and can buy a kit to swap out the leaves. but have to do steering also. 13+ have bigger brakes.

For the rear, sterling 10.25 or 10.5. Cheap, plentiful, e-lockers. Or maybe a 14 bolt.

 

Here is some info I saved off of here from a long time ago, just food for thought."D44 versus D60: But you will have a hard time finding a 60 with the 32.5" spring spacing, it'll have to be from a dentside. The '86+axles are spaced at 36", but are more common. Honestly the price you pay for one is way over rated. I happened to get one and put it in my truck, but it is just bragging rights to say "Yeah...I got a D60 front axle." They are over rated unless you continually are beating on it so hard you are tearing your D44 apart all the time.
The truths:
Yes it is heavier...doesn't do much but slow your truck down.
Yes it has a bigger ring gear...haven't broke yours, so why need to go bigger?
Yes it has bigger u-joint...good news is that likely won’t break on you.
The pitfall: (The outer shafts are the same diameter as the outer shafts on a D44) POSSIBLY INCORRECT (just a different spline count).
Instead of maybe breaking a u-joint you will likely break an outer shaft and good luck finding a cheap replacement.

The D44 held up for you for now, why change it? Also spare parts for the 44 are cheap. If you have 3:55 gears now and want to find 4.11s just find a D44 with 4.11s in already. I wouldn't pay more than $200 for a D44 front...they are very common. One questions for this would be what size tire are you running? For off road use the D44 is usually good 35" and under tires (yes there are many exceptions for this). If you rebuild the D44, do you plan on putting in after market (stronger) axle shafts and u-joints (or do you already have them). Load rating tests show that a fully upgraded D44 axle with good aftermarket shafts (there are LOTS to choose from and some are far better than others) is about equal to a stock D60 with 35 spline outer stubs.

Ok now you just upgraded your axle shafts... what does your current ring and pinion look like? If you are eating up teeth or snapping pinion shafts there is really no fix for this but to go to a D60... well there is one possible option and that’s a Dana 50 which is a kit to drop in D50 gears into a D44, bigger ring gear but same pinion shaft diameter. If you are going to regear and going to keep the D44 this might be a good time to look at this option for increased strength. Last question is... with the plow on the front and any extra weight are you over the D44's load rating? If you are really working it hard do you know if your D44 is still strait and are you overloading the wheel bearings? Might be time to weigh the front half of your truck and see where you are at. An axle truss might help, but I'd say if you are past the 44's weight, I'd move on to a 60."

 

What are you doing with the truck?

 

The outer stubs on a d44 are nominally 19 spline ~1 3/16 inners are 30 spline 1 5/16 (i believe this was the od of the splines but idr how I measured it or the exact numbers) they're thinner in the middle maybe 1⅛ and 1¼ and a 1310 ujoint by some other name they do make a 30 spline outer conversion but the d44 spindle is a bit thin so idk if you'd want that in a pickup whats even worse about the 19 by my eye anyways is its a very deep looking spline meaning the ~1/16 difference between the splines and the thin spot might have even been bigger

the dana 60 is 1 5/16 on the outers and 1½ inners again the thin spot is ~1¼ and ~1 7/16 and a 1480 ujoint also called something else because they're not normal ujoints I don't think the outers have to be as strong as the inners but on a dana 44 its mostly irrelevant since you'll break the ujoint first anyways

So yeah d44 quite a bit less and I've seen a few break all of them broke at the ujoint or bent a tube all chevy too not that I think it matters here they have the sameish parts

As far as buying a high pinion disc brake axle for 200 dollars idk where you live but I suspect you haven't looked at buying one of those recently

All that said you really probably won't break the 44 I've beat on them up to 33 and had one with 37s and a screamer of an engine spinning it but that was a drum brake d44hd with the bigger bits inside

Oh yeah the dana 60 is definitely not worth the price unless you get one dirt cheap

 

I appreciate all the info, as far as mine it was a copy and paste from a fellow member on here. I felt that is migth be helpful.

A little bit ago I bought a spare parts 1979 F250 D44 HP disk brake with a heim joint conversion on the drag link for $250. Complete lock in/ lock outs ect....
This is a 71 Bronco Dana 44 with added on disk brakes. 35's, rear spool and front locker.

 

See not broken just given a dramatically condensed maintenance schedule

 

No more like caused a dramatically condensed time line to upgrade the axle shafts. Both inner and outer 4340 chromoly with CTM u joints.