Let's see if i can explain this well enough. So for some reason i have always wanted to 3/4 ton swap my 79' F-150. Don't ask me why, i just have. I'm looking at buying a built big block with somewhere around 500 HP & TQ. So i'm curious as to what your opinions are. So obviously with the half ton, my truck has a 9" with 3.50:1 gears in it with i believe the Dana 44 in the front. Please correct me if i'm wrong. I don't know a whole lot about the axle portion of these trucks. I'm also looking at buying some new wheels too and i want to make a decision on what axles i want so i can order wheels with the correct bolt pattern.

Just like most people, my plan with the trunk is to eventually go through it all and make it nice. But god forbid it be slow. I'm getting off topic.

Would you rather:

Keep the 9" and Dana 44 in the truck. I know usually 9" are pretty stout. Should i be concerned about how much power it can take?

OR

Find a set of 3/4 ton axles. Dana 60 in rear, Dana 44 in front?

What would you do.

Also i have a few questions about this.
Since the front end is a Dana 44 already (I believe) couldn't you swap in 3/4 axles and a different ring and pinion into the housing?
What gear ratio would you recommend for a rig you can daily drive but still have fun with on the street or at the track? (I love drag racing but this trunk is all i have)
And do most 3/4 ton axles come with a limited slip diff? Or do some have opens? (I also enjoy burnouts. I'm 19)
I know the first 9" in my truck had a stock LS but my new one is a open. So what exactly do they come with?

Sorry about it being so long. Any advice is GREATLY appreciated!

 

Well you do have options.
If you change the rear to a Dana 60 with 8 lugs you can swap the outers on the front axle to 8 lugs as well and re-gear to match the rear. This is the easiest option.

The other is to change front and rear to dana 60's which will require fabrication and a lot of money.

Depends on what you plan to do with that big block and the truck. That dana 44 front can be built to handle a lot, but will never be as strong as a 60.

 

Well I figured I would just roll with the Dana 44. I'm not HUGE into off-road or hill climbing or anything extreme. I mean i like adventure and some fun out in the dirt as much as the next guy but 4WD will only be used for winter driving when it's icy, or if i get stuck playing in the mud or snow or whatever i may be doing.

 

Buy a cheap OBS 460 powered f250/f350 for parts. You get a big block and hd axles, I believe the 250s had the hd44s that'll swap over the 8 lug parts to yours, but I'm not 100% on it. The distance between the springs pads is different on the OBS front axle, so it's not a bolt in swap. Look for 4.10s in the axles if you want more performance. The diff gears will swap also if you need to regear your axle. A 500Hp 460 isn't hard or expensive. Probably the cheapest way to get what you want. Gonna get like 10 mpg. Look for a later model FI 460, might get 12.

 

For the front, the 3/4 ton usually uses a D44 also... with 8 lug hubs, usually twin piston calipers and probably other differences.

Big difference is in the rear. The 9" in stock form is good for OE power and weight and not much more. If you push it it way well break.

The 9" can be built... drag racers do it but quite expensive. For PU duty, a D60 is strong as originally built and can be found at moderate cost. I would suggest the D60 rear.

 

Just for the record I have seen 9" ford handle pretty well built 460's smoking 36" tires on asphalt. Not something I would recommend but I know they will. Also have seen 9"/dana 44 combos running large super swampers in some serious mud holes and handle that well also. I am not saying they are better than a dana 60. I am saying you might as well run them until they cant handle what you throw at them, and they might go for years. Spend your $$ on something else. Like Beer.

 

D44 is a 8.3 or 8.5" ring gear, 9" is 9", D60 is 9.75". You can get 9.5 and 10" aftermarket ring gears/carrier to fit a 9" housing, they're big $$$$ though. Larger gear equals more strength, generally. If its mostly a street truck, the 9" will hold up fine. It's shock loads that kill axles, not so much total power. Don't do neutral drops or side step the clutch, and watch axle wrap. A used LS rear 60 shouldn't be much more than a couple hundred bucks.

Just a matter of do you want to stay 5 lug or not. If you're not offroading hard or hauling heavy, 5 lug is fine.

 

Stock rear D60s suck. Small axle diameters and a crappy carrier that is prone to splitting.

Your 1/2 ton running gear is fine other than maybe getting a beefier carrier in the 9". Stock ones are weak like the D60 and I have broken them before. This would mean upgrading to an aftermarket locker.

Gearing is dependent upon tires size and cam selection. 4:11s for 33s and 4.56s for 35s is usually the recommendations for upsizing. If you get a very aggressive cam that needs high rpms for the engine to run good then the gearing needs to be even higher than that (4.56s for 31s or 33s and something over 5 for 35s)

 

Your current setup rear 9" should have 31 spline shafts, the 3/4 ton 60 you want to go to has 30 spline shafts. The strengths of these two are very similar. The 60 is full floating so that helps the shafts a bit by taking the downward load of your truck out of the equation. The only real difference between the two is the ring gear size although the 9" has a pinion nose bearing that the 60 does not have though.

For your front you have radius arms and coils. If you go to true 3/4 Ton you will have to change to leafs. If you leave what you have you'll have to swap everything outward of the knuckles to 8 lug to match the 8 lug 60.

I believe this is all a lot of work for very little improvement. I'd suggest leaving your axles as is and if you ever do brake something then change over then.

As a note most 70's ford D60's can't fit 35 spline shafts and the spindles are too small to be bored out. Dodge and some chevy d60 can fit them or be bored out to fit them though or maybe even came with them. So if you do go to a D60 you may want to consider a non ford D60 for its future upgrade potential or just step up to a d70, 14 bolt or sterling.

 

Regarding the axle swap...

The go fast drag racers use variations of the 9" rear end, not a Dana 60.

 

8 lug 3/4 ton just look mean. Most guys like myself like the looks of the full floating hub also. Look at it this way, no F 250 owners want to convert to 5 lug.

 

No difference on the D44 internals between 1/2 and 3/4 ton. Just the lug pattern. The outers all swap over. If you want to beef it up, beef up the internals. You can get the HD 31 spline shafts for under $100 each through Bronco Graveyard, and you can get Chrome Moly shafts and bigger Ujoints for your D44 front if you really think you need them. I rock crawl on 35s and even with a stock motor, that probably puts more stress on things than someone who wants to go fast on the street. You don't use 4x4 on the road anyways.