how much lift does the superduty springs give a highboy, i cant find anything on here to tell me the size of sd spring to buy for the ammt. of lift that i want. i would like about 3" taller than stock highboy, with a 390 in it. so do i buy a 2", 3" or 4" lift sd spring

 

Many variables affect this, and there is a different answer for each truck. Engine combos, will have the biggest effect.
Big difference between an engine with aluminum heads and headers, no winch, blah, blah, blah. You get the idea.
At any rate, the smaller springs seem to run real close to advertised lift numbers, bu this too changes from manufacturer to manufacturer.
For minimal lift under a 73-77 truck, I might suggest a 4" spring.
Here is why:
You will have to remove the military wrap leaf to get the spring to fit in the stock front hanger. Removing this will add flex, and provide a much better ride, bit will kill some lift. BY starting out with a 4" leaf, you can afford to kill some lift, and you should end up with approx the amount of lift you desire.
Again different manufacturers will have slightly different overall lift values, but this should get you in the ball park.
Now,,,,,,,,,in this case, for such a small amount of lift, is the SD spring option really the best one? Skyjacker leafs are not such a bad choice, and there "velvet ride" leafs are 1" shorter than the SD spring, so there will be no modification required, and the ride is still pretty good.
These are direct bolt in's and dollar for dollar might be a better alternative.

 

75f350, you mention the SD springs being an inch longer, and mods needed. What mods are needed to run the SD leaves? Does one have to move the rear shackle mounts rear-ward to compensate? or build a new front cross-member/spring hanger? I have toyed with the idea of building a new front cross-member/hanger to get me a small lift while also making the front cross-member stronger and include a receiver.

I messed with trying to "loosen" the front spring clamps last night. That is kind of a pain. I was not sure what I was doing either. I decided that loosening meant to straighten the tabs and then re-bend them higher up so that there is more room in the clamp. It did not seem to help the ride though. My springs are pretty worn though, they have grooves worn where the end of the lower leaf rides on them. Maybe they are binding up? who knows.

 

Scott:

Eventually I am going to write up something that covers this. After I broke the truck last weekend, I have been a little busy getting it back together, and doing it in such a way that will prevent it from happening again. You also know that I have been spending time on those diff covers, lol.
At any rate, this seems like an appropriate thread to straighten some things out.
The SD springs are 1 inch longer than the stock 73-79 trucks. These measure 53 inches compared to the 54 inches that the SD uses. This is good and bad at the same time. Good because it creates a little better shackle angle, and improves both ride, and articulation. Quite a bit of extension is obtained, where it was not available before.
Bad because the length of the stock shackle does not permit the spring to lengthen as it compresses without hitting the frame. Even with mulitple attempts at flexing the truck with a forklift in the shop, I did not take into consideration the impact a large jump, or getting the truck airborn would have here. I compressed the spring far enough to allow the spring eye to hit the frame, and as the shackle tried to pivot to accomodate the spring length change, it ran out of room, and was able to strike the frame. Since it did not have any way to release the stored energy, it could only do one thing,,,,,,explode! It did, and while everything (except the shackle) survived, I learned quite a bit. While I doubt most will dive thier truck this rough, I did, and it failed. I will update you with my fix, as I am still currently working with ChaseTruck on the relocation of the pivots, and maybe going to make some crazy sick long shackles. More as I progress.
In the mean time, this problem is more pronounced with Highboys, since the hangers and shackles are shorter. I used 5.25" long shackles, and the stock front hanger location. I fooled around with the thought of moving the front hanger foward, but this presented a couple of problems. It would move the axle foward (not a bad idea really) and would still present me with a rather vertical shackle hanger. This vertical shackle angle was something that I was trying to eliminate in the first place. I was concerned that the springs would ride rough, and this would be counter productive. Imagine using these springs, making new hangers, and still getting a rough ride. I would have been upset to say the least.
I have had a little better luck running the SD springs in a later model truck (77.5 to 79) since the hangers are longer, and so are the shackles.
Keep the tires on the ground, and speeds slower than say 60 mph over some whoop sections and the trucks should never encounter what mine did. Bet that will never show up on a car fax report, lol.
As you all may be aware that the spring fasteners are a different size on the SD springs, so there will be some drilling. You have the option of running an 18mm front bolt, without modifying the bushing, and only drilling the hanger, or going to a 3/4" bolt, and drilling the hanger, and making the bushing a little bit larger. It is almost there, but needs a little help. I chose the SAE route, and it seems to be working just fine. In the beginning, I used a bushing within the main bushing, and some grease. This was a critical mistake, and it did not survive. Ah the joys of trial and error.
I have considered this for most DIY guys, and while I like the springs, and out of the box will work for most, with just the normal modifications. Re-drill for larger mounting hardware, grind spring bushings to fit inside of the early hangers, and for 73 to 77 trucks, make a longer shackle, and remove the military wrap leaf. That is about it.
Just for my application, I also flipped my u-bolts so that the nuts are above the spring. This keeps them off of the rocks that I love to run. Nice and smooth under there now, and it does get rid of a little weight.
Now a guy could get creative, and use a set of later 77.5 to 79 front hangers that are bolt on by the way, and since they are a little longer, they will provide more lift, so instead of a 8" spring, one might be able to use a 6" unit, and get an even better ride. Combined with the longer shackle, it should provide adequate travel during a heavy pounding. Again, there are probably only a small percentage that drive thier trucks like rentals, the way Red sees. Poor truck!
The SD spring is a good alternative for high trucks that need additional clearance for big meats. Talking probably 39.5 inchers or larger. This is because there are springs that are made for our era trucks that work well for lifts less than 6 inches.
Biggest thing is to know that these SD springs are not direct bolt on units, nor designed as a kit, but is a cost effective solution, and the availibility is second to none. I believe that convenience stores are gonna start stocking SD lifts, right down from the small block chevy parts, lol.
Easy to find, and not too tough to install. Tuning them for optimum performance can be a little tricky, but I keep at it until it is the way I like it. Some may go ahead and go with a ride that is a little more firm, and that might work for them, and require even less work.
I guess the important thing here, is to try to do the least amount of work, and obtain the best benifits. The SD spring has all of this, but does require just a little bit of garage time.
Good way to kill a weekend, and enjoy a couple of adult beverages.
Hope that may have cleared things up a little.


Now to answer your question regarding the front reciever. Did I send you the pics of my reciever? I used a rear reciever for a later model F150, and turned it upside down. This made it higher in the fram rather than lower, and I fit it between the frame horns up front. This placed it perfectly behind the front license plate. I then made a license plate holder for the reciever, and the plate now resides in the reciever. I remove it when I am off road. Strong enough to tug from, and I can place the winch craddle in it, and the shackle mount rides right in there. Super cheap, and easy.

 

I would like to have seen this spring failure, I bet it was loud. I hope ol' Red faired ok on the landing.

I actually have a receiver that looks identical to the one you used. I want to build a stout front cross-member that looks beefier and can take the abuse of tugging and maybe winching if I ever get a multi-mount unit. I am also building a new front bumper for it, I live in big game country and would rather hit the suicidal animal than run off the road trying to miss it. That and I like custom bumpers if done right.

So......If I built the new front spring mounts and lowered them from the frame a couple inches and extended the shackles at least the same amount, I should be good to go? I am not sure how the extended shackles will affect the springs, I assume I would get more down travel out of them. I would also box the back side to the shackle for strength to prevent them from bowing. It looks as though the stockers are made out of 3/8" material, so I figured I would make them out of 1/2" plate since they would have to carry the same abuse/load over a greater distance (poor engineering terms I am sure). If I did my setup like this, it sounds as if SD springs would bolt right in. I only want a max of about 4" of lift, I plan on using this truck as a work horse and a toy so I don't want to make it too tall to load stuff in.

The next question is......what is the best way to lift the rear without lowering the load capacity and at the same time smoothing out the ride some.

Ed, your the man....We should be neighbors......

 

Make Ed show some pics of the shackle design I had him do. They are more stout than 1/2" plate and weigh less!

As for lowering your pivots to get the springs away from the frame - I THINK this will work, as long as everything is moved straight down in a set number increment. Meaning if you lower the front pivot straight down 3" - the do the same for the rear. Personally I think that can work with you, as you can make a very strong rear shackle mount, and get yourself more clearance from hitting the frame. You can then use the same length shackle as stock and not tweak your castor. I can show you a quick Cad drawing of what I mean if you like. I can't post it here, but I can send you something in PDF format if you email me or PM me and remind me about this thread.

The problem with the setup I mention above is that you will gain more lift. I know this is not a problem for some, and it can be cured by running a 4" lift spring when you want 6" of lift etc., but for guys like me that enjoy my low C.O.G. this creates an issue...

Any thoughts on the above Ed? Also - are you doing the 12" shackle and above frame shackle mount I told you about, or are you still going through the frame?

Oh - and Scott - big red didn't yelp too much - at least I couldn't hear anything over the manly growl of the 4 banger toyota motor!

 

I got a question for you guys. Ive got a 79 1/2 ton and i was wondering if the shackles from the rear would swap to the front of my 76 high boy. I noticed there was a mention that the later 70's trucks have longer shackles, just wondering if this swap is possible so that i can run SD springs in the front of the 76 with out having to fab or purchase any longer shackles. Thanks for the help.

 

Steve:
Red simply went back together the same way it was before I busted it all up.
I will use the grocery getter as the mule to experiment.
Will have to see what happens.
As far as the above question regarding the use pf rear shackles up front, the answer is no. Rear shackles and front shackles are different, and are not interchangable.
If you have a 1/2 ton, u do not have front leaf springs anyway, so this has me a little confused.

Getting back to the use of longer shackles and lower hangers, this is a great idea, and can easily work. Lengthening the same amount will not have a negative effect on caster.
This is not any different than later model lift kits that are simple hanger kits.
The 75 Grocery getter used 6" springs, and a 4" super duty hanger kit. Thats how I was able to clear 44's.
Matter of fact by using the super duty hanger kit, it eliminated the need to modify the springs bushings and such.
I dont know, but making some hangers is a real easy solution.

 

So I started on the front cross-member/spring-hanger last night and welded the receiver tube into it this morning.

I need to know how much room I need for the military wrap on the SD springs.

I also have not decided how much I want to lift it with the hanger and shackles. I think I may make the shackles a bit longer than the amount I drop the front, My theory is to gain caster. I have a bunch of caster on my short box and it drives better than any of the new SDs I have driven. It also has cross-over stearing etc.... What is the smallest lift available for the SD leaf springers? What is the best way to lift the rear to match? Have new springs made? Does some one make a lift spring for the rear?

I also like a lower CG and a lower load height, I want to build a sled-deck for the bed so that I can haul both of my sleds without a trailer.

On another note, I may be trading my 'Chero for a pair of axles. D60/D70 out of a '92 Cummins. I didn't really want a Dodge side D60, but it may be good trading fodder.

 

Hey Ed did you ever get your shock mounts figured out? I know you said somethin about them almost hitting the hood. Id like to see some pics. Hopefully ima start on the crew soon.

 

Did you at least put in the "real" shackles and loose the testers? I still wanna see those. I'm sure others here would like to see too. Plus then they can see how to REALLY make a shackle...

 

Dave:

The super tall shock mounts are in the "grocery getter", and those are, or used to be way up there. I went a different direction with that truck, and it is now concentrating on more suspension extension instead of compression.
I feel that I can keep a lower COG, and still get over some big obstacles, and maintain better clearance. I did lower the truck, and while it still sits on 44's, it feels better on the ground, and quite a bit more stable.
My most recent set of mounts under the 74 truck are still pretty tall, but only rise as high as the inner fender. They do tuck all the way up to the very top of the inner fender, and can accomodate a 14" travel shock. This mount is centered to accomodate 7 inches up, and 7 inches down.
Most recent incident used up almost all of the up travel, or compression. Little bit frightening.

Steve:

While I have not yet installed the new set of shackles, (I am still up in the air about the pivot) I did repair the broken one. I simply made a new set that was exactly the same as the old one. For the moment, I also repaired the old one and it now sits in the spare parts box in case another problem should occur in the sticks.
I will also try to keep Toyotas with King shocks, and long stretches af dry lake bed with whoop sections away from Red. Big old mud trucks just do not seem to like this type of terrain, lol.

 

that's OK - whole red doesn't like the fast sections, the black beater doesn't like rocks - as you can tell by the rocker panel.

Oh - and I noticed another bit of carnage the other day. It seems I bent 1 of the 2 5/8" or so bolts that bolts the front carrier and axle tube to the crossmember. It seems I really need to get that front skid plate going!

 

Thats right! I forgot that the "little truck that could" was vertically challenged, lol.
Poor little truck. It was a trooper on the rocks though, and did real good in the sand.
Guess you just need to stay off of the rocks, and I need to keep red under "warp speed" when the terrain gets a little bumpy, lol.

 

It sounds like you guys have a good time.

I need deeper pockets.....