SD leaf springs:
The leaf spring bushings are slightly larger than the original hanger, so grinding the bushing down is a reasonable solution. This only has to be done to the front of the spring. For the rear, I replaced the pivot bushings, and used an off the shelf Toyota poly bushing used in 80's era 4x4's. These bushings had to be modified a little to fit, but worked perfectly. By taking a small torch to the old bushings, they popped right out, and left a small metal insert in the pivot itself. I was able to leave this in there and not fight it to remove. This can be tough to remove while the pivot is still in the truck.

By taking about 10 thousandths off of the bushing itself, it went in with little trouble. This is almost a perfect fit. Then I lubed up the metal insert, and viola, it is the same width as the spring bushing, and a perfect fit. Front end is done, and everything lines up. Oh, if the leaf is equipped with a military wrap design, it may have to be either cut or removed to fit the smaller hanger of the highboy. Later 78/9 bolt on hangers are larger and fit the military wrap leaf. Longer front shackles will have to be made, and the new length should be right at the 5.75" mark. This will provide enough room for the spring to flex and keep the spring from hitting the frame. This has been a problem I have been working out over time. Quality material and thick steel has to be used here. Too small or thin and the shackle will flex.

For the rear, the popular thing to do is the shackle flip. Since this requires the removal of the rear hanger anyway, half of the work is already done. Now since the perfect donor hanger is to use the fixed hanger found at the front of the rear spring, this means that another hanger needs to be installed where this one was removed.
Step by step:
Remove both hangers, and throw the inverted rear hangers in trash.
Purchase, a longer hanger for the front of the rear spring. 1/2 ton, or 2wd hangers are longer and will provide more lift. Make sure that the width is the same as the spring. Chevy hangers can be used here too.
Align the 64" rear spring so the axle is centered in the wheel opening.
Install the newly purchased hanger in the front of the spring and attach to the frame.
Install the original front hanger in the very rear of the spring and hang the shackle from this. Bolt up and verify that all hangers are level. Use a quality fastener here.

This will net some pretty serious lift and much will depend on the rear spring that you use. This 64" spring is easy to find in the salvage yard, and will cost way less than new springs.

I am telling you, this system works and works well. Not expensive either. My front leafs ran about 500 bucks for the pair, a great friend gave me a set of leafs (thanks again ChaseTruck754) and my hangers ran about 40 bucks from the salvage yard. This clears 40"rubber, and flexes like crazy.
Rides well, I mean extremely well, and I still tow a car hauler with a rather large 1 ton truck with this truck.
When looking for spring hangers, don’t limit yourself to just this era of ford trucks. They are limited in numbers at the salvage yards and just try to find a new one at a dealership. That being said, you can use a later model spring hanger, the hanger does not care. I suggested that one look into chevy hangers, if you are going to remove the spring from a 2000 plus silverado, grab the front hanger too. Use this on the front of the spring, and then use the factory ford one on the very back of the spring for the shackle flip. This is a very inexpensive way to lift a vehicle and still use the comfort and versatility of the newer spring.
I used:
Front:
8" BDS front springs from a 99 to 04 "gas" Super Duty
Extended my front shackles, they now measure 6 inches from center to center
Custom front shock mounts (17" travel front shocks)
Stainless braided front brake lines
Crossover steering (Dana60F) and power steering conversion using Saginaw 16:1 box
U bolt flip
Rear:
Stock 64" long 3500 series chevy silverado rear leaf
2001 chevy silverado 1500 series front spring hanger mounted lower to provide more lift
Stock Ford front spring hanger installed in the very rear to accommodate shackle flip
Relocated shock mount to accommodate 14" travel shocks
Stainless steel brake line
1. They are quite simple, you will have to follow some of my old threads, or read some of the posts where we have discussed it in great detail. You will have to cut or remove the military wrap leaf to clear the small spring hangers, and you will have to make longer shackles. The SD springs use larger fasteners so you will have to drill the hanger to 18mm or step up to 3/4" bolts. The shackles are going to get drilled anyway, so you can go with the metric stuff or use 9/16" SAE.

2. My set up on the red 74 (now its a 74, as I have since sold the 75. I had two identical trucks a coupe of years ago, and they sort of evolved into one truck) is a BDS 8" front spring pack with 2 leafs removed. Custom shackles to allow for additional travel, custom front shock mounts using 2.25" diameter smooth body shocks, 17" stroke.
Rear is a bone stock 3500 series Chevy Silverado leaf pack with zero lift, stock 4 inch block and a shackle flip using stock hangers.
That’s it, it clears 39.5" boggers. Unfortunately I do not run bump stops so my fenders take a beating and are always wrinkled.

ADVICE#2
Now we are starting to see why alternative lifts are becoming popular.
With 10 inches, one could assume that you have a desire to clear 44" rubber right?
I only ask because, 10" SD front springs will give you greater than 10 inches of lift over your stock height.

You will have to grind the spring eye bushings a little to fit inside of the 75 spring hangers. A few minutes with a flap wheel and an angle grinder will make short work of this. You will also have to make longer shackles for the front springs. If you do not jump the truck, or get overly aggressive, you can get away with a shackle that is 5.25 inches. This will clear the frame, and allow a decent amount of pivot. The shackle angle will increase with the use of the longer SD spring, but this angle is good, and contributes to the better ride quality. At this time, you will probably want to replace the front pivot bushings. I can guarantee that your 30 year old ones are shot.
You will want to be aware that this extended shackle does affect "caster" so caution must be used when making this modification. Too long, and the pinion angle gets whacky, and the truck steers very slow.
You will have to remove the entire leaf that makes up the "military wrap". This is the second leaf in the pack. The diameter will not fit in the stock hanger. I have run with the entire leaf removed, and have cut the wrapped portion out of the pack. Removing the leaf itself allows for more flex. I have yet to encounter a failure, or bend a main leaf after a removal. I am pretty hard on my vehicles. After this, the spring mounting hardware will have to be addressed. The bushings are a larger diameter, and will require you to drill the hanger to a larger size. You can either drill to 18mm and buy an 18mm bolt for the front, or make the bushing larger to accommodate a 3/4" bolt. Since you are making your own shackles, you can use the stock size upper bolt, and drill the lower to the appropriate size.

For the rear, you have many options here, but the best so far, is to ditch the stock leaf all together. You will probably consider a shackle flip, and since you are removing the rear pivot, you might as well remove and replace the front one as well. What I did was remove the front fixed hanger and mounted it to the rear. This creates a new mount for the shackle. For the front fixed mount, I replaced mine with a late Chevy hanger. It was longer and created more lift. These lift figures will vary depending on how you mount it to the frame. The longest hangers can create as much as 6 inches of lift when combined with a shackle flip.
Alright, so you have the hangers off completely, and now you have a few options. The best option here is to use a 64" long rear leaf, also from a late model Chevy truck. 2wd, or 4wd this does not matter, and it will fit the shackle, and hanger from your highboy.
I used the very end bolt holes as a reference for my new bolt holes. The very outside holes became the inside mounting holes. This required me to drill a bunch of holes for the new 1/2" hardware, but I was confident in axle alignment because I was able to use 4 existing holes. Shackle angle is at 23 degrees, and has a bunch of flex with a 2wd 1500 64" stock leaf. Longer shackles will change this, blah, blah, blah, you get the idea. Feel free to cruise around and see some of the other mods required for this complete modification.
Weight capacity is very limited if you use a 1/2 ton rated spring. The fix here is to use a 3/4 ton spring.
Lift figures will vary based upon different springs, and which hangers you use. It is very easy to create the 10+ inches of lift with this method of lift, and though it sounds rather complex, it is really pretty easy, as long as you can read a tape measure, and are careful to attach everything with safety in mind.
These rather flat springs really flex well, and offer a fantastic ride over the stock units. Because they are flat, they do a pretty good job of controlling the axle, and help to eliminate wheel hop. I can really lay on the throttle, and spin up the rear tires in any condition, and the axle does not hop. It does get a little weird if I lock the brakes up, but this has only happened once or twice.
While this combo sounds like a bunch of work, when compared to the amount of work required for a similar modification, the rewards are well worth the effort.
Shock lengths become the limiting factor, because the springs at this point are capable of more travel than the shocks can travel when using the stock mounting locations, but for the weekend user, the stock locations will be fine. For a more aggressive user, new mounts that are farther apart will be a benefit.
I am still working out the bugs for additional travel, but I am using just about all of the stroke of a 14" front shock. Not bad for such a large truck. Fenders really suffer (Thanks again to Steve / chasetruck754 for all of the fenders I keep crushing, lol), a little because of the additional flex, but this can be eliminated with the use of an aftermarket bump stop.
Guess I should state the obvious: brake lines, steering, drive shafts will all have to be addressed.
I use 8 inch lift front Super Duty Springs for a 99 to 04 gas truck.
1) Grind SD spring bushings to fit existing spring hangers
2) Drill hanger and shackle to accommodate larger mounting hardware.
a) Drill hanger to 18mm or 3/4". If 3/4" is desired, ream bushing as well.
3) Make a new shackle that is longer than stock. 5.25" seems to be alright as long as the shackle bushings in the pivot are new.
a) Replace shackle pivot bushings with toyota poly bushings, and you won’t have to remove the steel sleeve within the pivot itself. This is difficult to do. Using the toyota bushing eliminates the need to grind and remove the pivot. (Toyota 4X4 early 80's spring bushings are almost a direct fit.)
b) New center bolt can be 9/16" and all new hardware should be used. This will also fit the new spring very well.
4) Some springs will require the removal of the military wrap leaf. This leaf may be too large to fit inside of the front hanger. Removal also increases overall wheel travel.
5) Shackle angle is increased, so verify that the shackle will not strike the frame during suspension cycles.