Yeah the front wheel well def looks bigger now that you point that out on that truck. I think I might use a shackle flip in concern for the rear pinion angle and some 6" rear springs. I still think I will still run the 10" front springs, just cuz. No good reason really.

Do you know how close the later model(80-96) springs are to working out back? I have them both out there, I spose I could go measure, just being lazy LOL.

 

I do not know first hand. Since I usually ditch the heavy rear springs for better riding and performing units, I simply do not know, but as I recall the alignment, or center pin is offset, and will not center the axle in the wheel well.
Notice pops truck has the front axle foward, and the rear axle towards the rear. This was done on purpose. Better approach and departure angles.
This is a slight example, but I do believe that the later springs are 3 inch wide, so you will need different hangers, and the pin is way too offset to work reasonably.
I guess anything can be made to work, but if you were gonna go through all of this work anyway, why not use a longer, and better performing spring like the chebby 64 inch unit. Those bad boys are real nice.
Again, the rear is not too bad, and there are enough options to get you the results you are after.

Dave has the right idea. You could fab up, or use some 78/9 hangers, or even a SD hanger kit, and bolt it up to your frame, and run a sightly flatter spring.
I now clear 44's with inly a 6" SD spring, and some mild hangers.
Pretty good flex too.

This is what makes working on these old trucks so much fun. Man I am all motivated now. I may have to run over to the shop and work on something, lol.

 

Do 78/79 rear leafs have the same geometrics as highboys? There are 6" springs available for them, shackle flip adds another 3" that'll put me right up there. I have to replace the rear shackles anyway, I could just upgrade to the 3" springs. After that I can swap out the factory block for a 4"-6" angle block for pinion correction and/or add'l lift.

You know, I was just looking at this divorced NP205 on this truck. It would be super easy to lower it an inch or so to help with angles.....Any thoughts here?

 

I do not see why the later spring (78/9) would not work, but it will require you to change out the hangers anyway. If you do this, then just about any spring will do, and you can even use the springs that you mentioned earlier.
You will just have to re-install the hangers to accomodate the wheel well opening.

As far as your NP205 Tcase. It is easy as pie to relocate, but the results are minimal. Since you are dealing with a divorced case, the front angles are pretty good to start with, even at a high lift. Since the output for the rear is centered around the input shaft, the rear output does not change when the case is re-indexed. Does that make sense? The case will just pivot, and the rear output will remain unchanged.
This re-indexing will only be advatageous if the front DS angles are too great.
I usually rotate my divorced cases up to gain some clearance.
The real fix here is to install a high pinion front axle, and driveshaft worries are a thing of the past.
A divorced case and a high pinion front end is a dream on front angles.
Double cardan rear shaft helps with the increased angles. If you are going to try to modify the case to make the rear angle better, you have quite a bit of room to move the entire thing foward. This will require you to modify all three shafts, and the shifter linkage, but even a couple of inches is a great benifit to that rear shaft angle.
Just a little food for thought.

 

I suppose I'll worry about shaft angles when I lift the truck. Need to have a reason to fix it before I should worry about fixing it I guess. I am def gonna upgrade to the 3" leafs, prolly just stick with 78/79 lift springs. that way I don't have any moving of things to mess up LOL.

Know of any good place to get new or good shape 78/79 rear leaf front hangers? you can get new rear ones pretty easily about anywhere, but I've been looking just now and couldn't find fronts.

 

As i recall, you can use later model units, and the stealerships stock them. They are not expensive at all, and you can find some pretty long ones that will help with additional lift.
yeah, in this case, the dealership will be your best bet, and the final install will look clean and factory.

 

question:
if you didn't need to correct the pinion angle, could you toss out the lift blocks completely? (i heard that lift blocks contribute to axle wrap) - is it possible to get springs that give you 6" of lift without blocks?

 

The tallest springs for the rear of these trucks are 6" so yes you can get 6" of lift without blocks. I however am trying to achieve 10"-12" of lift, so I will more than likely need some sort of block under the spring. I figure the 6" spring, the shackle flip, and the 5" or 6" block(in place of the factory 4" block). this combo should put right up where I want to be.

Yes lift blocks make axle wrap worse but I'm not overly concerned with that, I'm building a driver, not an offroader.

 

The 80 and up springs wont work. To short and the centerpin is off. As for the 78/9 springs workin you can sheck part numbers but a 6" lift for a 78 is a 4" lift for a highboy. Just get some SD leaves

 

Ok one more thing youll have to watch if you swap to 3" rear springs. They have alot more arch than the highboy rears. Take a look at a 78/9 F-250 rear frame section. It arches up alot more than a highboy. Like a few inches. That will make the 3" rears actualy lift a highboy rear in factory form. Trust me bub ive been researchin a 4wd conversion on my 79 crew for 2 yrs. Its frame is the same as a highboy so ive learned alot abotu the differences of pre 78 to the 78/9s

 

If you know a bit about fabricating or know someone who fabricates its a free 5-7" of lift. (not finished, have a little more reinforcing to do)

 

hey, if your not worried to much about money, check out national spring. National Spring i just ordered a set of 12 inchers for my 78. they are not the cheapest but all i got to do is bolt them in. also we just finished a 79 f350 by droping the spring hangers. very cheap!!! 2x3 thickwall square tubing is all you need. oh and on the rear, if you have a reese hitch, just flip the rear hanger nd weld it to the hitch. 7 inches easy. we also droped the front rear hanger 4 inches. we got about 13 inches all together and room for 49s.

 

ok i need help with my project (baDD).

here is the scoop. i have a 1972 ford f250.. i boutght the truck with the cab of because they were painting the whole frame.
well the last owner gave up on the truck and i bought it for 500.
but back to my problem. they started to custom make a shackle reversal in the back. they replaced the forward rear spring hangers with longer ones of a 2wd pickup. (this droped the spring mounts much farther down atlest 5") in the back just before they gave up with the truck they ground of 2 of the factory rivets so i know they were replacing them. i asked a friend who did the same thing to his truck what i had to do to finish my lift project. he said get the same spring hangers used in the front and mount them up.. ok fine i also got 6" lift springs in the deal. atleast he says they are. when i put a bolt in the front of the spring i swung the spring up and the rear hanger was about 3-4 inches away from the spring.
my question is when i put the rear hanger in do i need to move it forward..or do i have the right springs?? how long are factory springs. this way i can compare them to the suposedly 6" lift springs i have..

project at a stand still

 

Welcome to the site.
This is a pretty old thread, and perhaps some new stuff has come in to play, but after reading a little most is still pretty accurate.
At any rate, as long as you have to install the rear hanger, you might as well install it where you want regardless of which spring you have. If you perform the shackle flip, you will not be using the stock mounting holes anyway. In order to achieve the proper shackle angle, this configuration will require that the pivot be located further foward anyway, so get one up there, and set some weight on the truck and verify the angle. It sounds as though a previous owner started something that is not exactly stock so providing you with the magic answer will be close to impossible. Too many variables here, and maybe the previous owner used a different style spring. Fortunately the rear springs are pretty easy to set up.

 

i Bought my 9" rear springs at compitition leaf spring and took out the factory 4 1/2" block. I wouldn't recomend them though cuz they messed up a bunch of stuff and i allmost lost them in the mail not to mention they were to long to wide and bushings were to small. I just bought my front 6" lift springs from Carrier Spring in Canada. So we will see if they do any better.