well here's how it begins alot of talk been going on in this forum and the dentside forums haven't seen much picture threads about the 99-04 super duty leaf spring swaps in the bumpsides so i'm giving it a try test subject a 71 f250 4x4 crew cab i'm just getting started so keep an eye open for updates and pictures to get started i got a 8'' front and rear leaf spring lift kit from skyjacker starting on the front here's where i am and came to a snag already leafs bolt into the front solid mount but bushings will need shaved down about a 1/16 on each side to keep it even and bolt holes need enlarged i'm using the old bolts for now to test before i get the right size front axle ended up being in the same position but the problem so far is the rear shackles they tilt forward instead of backward question for you's the rear shackle must lean backwards toward the rear of the truck right? and whats the ideal angle? here's the pics of problem 1 any suggestions to fix this? can't move forward until this is resolved.

old leafs shackle angle




super duty leaf shackle angle

 

need to measure your leafsprings factory and then the superduty. Not sure on lenghts of what you have. If one is shorter than the other thats the answer. measure from eye to eye with the arch of leaf not just straight across. next is if leafs are the same length and the company you used just added some arch to your spring and this will make them shorter eye to eye. now also if your trucks front weight is to light for this setup it doesn't compress the spring lenght to its designed application which might be part of your problem. need to get info on what the springs are rated for in spring lbs. like 3400 or 4000lbs?? On the angle of the front springs I would say angled back a little but not all the way back with the load of the truck on leafs. this allows the truck to flex in front suspension a little better. One of the problems with flexy leaf suspension is your drivelines sometimes will seperate due to to much travel in front suspension. need to get driveline length accurate. So if your hangar is forward it will not allow as much suspension travel down compared to a hangar in a rearward angle. On driveline really look close at your splines and make sure your slip yoke isn't about to seperate or btm out if suspension is totally compressed. I'm more of a link suspension guy or radius arm front suspension kinda guy. your driveline really isn't a issue if suspension is compressed or extended. I can move my suspension 14" up and down and my slip yoke movement is about only 1" and keep as much slipyoke strength as possible. my 1970 ford will have a modified van coilspring suspension which is radius arm style but will be extending my radius arms a little to help out with ride quality. hope this answers your question or atleast heads you in the correct direction. also are your center pins centered or are they offset in leafspring. like 30"x24" or 30" to pin and 30" just curious and need to compare both leafs. catch you later and you really need to check out race-dezert site really cool truck this young man is building. Its a 1971 ford starting from scratch to what you see in the end. 14yo1971f-250 in the shop section.

 

The reason your shackles are at the wrong angle is that you don't have any weight on them. They will point the correct direction when loaded and the springs flatten out. I run the stock SD springs on my '71 HB. They ride better, flex better, and I gained a couple inches of lift. I also am running the 64" shivy leaves in the rear.

 

I had the front SD springs both on and had the front axle in position I then sat everything down on the ground so what weight I do have on the front would compress the springs and try to get the shackles to point back they don't seem to want to flex enough and I can't imagine them to tilt back far enough even after the engine trans and front clip is on me and a buddy both were standing on the front where the motor would be as I already thought of the missing weight being the problem and the springs barely moved

 

Could you possibly get me the measurements of your front SD springs? From eye to eye including the arch and another from eye to center axle pin to eye I'm thinking since I got the 8" lift my problem is I lost the extra length of the springs due to the extra arch I have since I'm not using stock SD springs therefore pointing the shackle in the wrong direction even with everything on the front I don't think they'll sit far enough back to give me proper shackle angle

 

You and your buddy must be pretty heavy.....

The engine, trans, and front clip probably weighs close to 800lbs wet......you guys are probably half way there....

 

I do realize that we weren't half the weight of what would be on the front end but I just can't see it happening I got to measure the old springs just got to wait till it stops raining so I can go outside

 

I believe the SD springs are about 6" longer eye to eye. You'll have to measure along the arch to get an accurate measurement. The other half of the weight will make a ton of difference in sag. What brand springs are you running? Are they a soft model or stiff?

 

I'm using the skyjacker softride 8" lift leaf springs I'm going to call them and ask what the spring rate is on them I think ill end up needing to make a bracket and mount it on the underside of the frame and attach the shackle from that I made up a drawing on my computer at home ill try posting it when I get a chance

 

Put equivalent weight on the nose, you'll see, it will work. Did you get Diesel springs or gasser springs? Don't do anything drastic yet. You have to engineer the entire package. Put the weight on it. Trust me.

 

I'll be putting in the motor within the next 2 weeks hopefully I'm putting in a 460 with a zf5 trans I'm going to order the motor mounts today or tomorrow so it'll be alittle until I can get the weight on it I got the skyjacker springs there suppose to give a gas 8" of lift and a diesel 6" lift these part # springs are the same for both called skyjacker to ask the difference and that's there reply got to call again forgot what spring rate is

 

Sounds like a good package there. Those springs will squat right down with that elephant in there.

 

What front axle you runnin' there? What are going to use for a steering box?

 

this truck is getting heavily modified all at once here's what will be done i got a 460 engine out of a 79 f250 4x4 also for steering i got the power steering setup out of the same truck along with a DANA 44 front disc brake axle DANA 60 rear. i picked up a zf5 transmission from a 91 super duty with the parking brake on the rear of the trans wanted this style because i'll be converting my rear DANA 60 to disc brakes i ordered the motor mounts for the 460 to fit in this truck yesterday i'll post pics of the install in my other thread about l&l motor mounts i wwent with autofab mounts instead was reccomended to them and after looking them over i think i'll like them more then the l&l's more sturdy structure

 

just got off the phone with skyjacker and the springs i'm using the spring rate is 557 the part number i bought is F965S for 8'' gas lift 6'' diesel is this a good enough spring rate for the 460? or is it to low and would a bigger rate be better in my case? after installing the fronts and jacked up the rear to level it i was thinking of maybe going to the skyjacker part number F985S which is for a diesel 8'' lift and has a spring rate of 600 would this rate be fine with a 460? i measured the super duty leafs and they are 28'' from center of eye to middle of spring where the axle stud is both sides are 28'' eye to center whick means center of eye to eye i have a total of 56'' arch included anyone know what the stock leafs length is? still raining here so i can't measure them. heres the illustaration i drew up if i cant achieve proper shackle angle and how i was thinking to correct it the top flat part of the triangle will bolt to the underside of the frame and be welded also.