Superduty leaf springs
Post Fiend
Joined: May 2004
Posts: 5,277
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From: St George, SC I-95
Actually it will ONLY work on the front.
Inhales deeply....
Super duty leaf springs are almost a direct bolt in swap. You will need to drill the front spring hangers out to 9/16" (not 5/8") for the correct size 9/16" grade 8 bolt. A flap wheel is necessary to shave a little off the poly spring eye bushing to get it in the hanger. Other than that its a bolt in deal.
SD front springs will ride much better because the frames are much wider and the added leverage gained by the narrower 77.5-79 frames will lower the spring rate. The part that I dont know is that if a 4" SD lift spring will give a 77.5-79 F250 a true 4". My guess is more (maybe 5") due to the heavier weight of the SD engines even over 460s.
Inhales deeply....
Super duty leaf springs are almost a direct bolt in swap. You will need to drill the front spring hangers out to 9/16" (not 5/8") for the correct size 9/16" grade 8 bolt. A flap wheel is necessary to shave a little off the poly spring eye bushing to get it in the hanger. Other than that its a bolt in deal.
SD front springs will ride much better because the frames are much wider and the added leverage gained by the narrower 77.5-79 frames will lower the spring rate. The part that I dont know is that if a 4" SD lift spring will give a 77.5-79 F250 a true 4". My guess is more (maybe 5") due to the heavier weight of the SD engines even over 460s.
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Senior User
Joined: Jan 2008
Posts: 439
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From: Yuma, AZ
I had heard that rears would work. I'll see how much they are. There's a superduty shop SDHQ, and i wanted to see how much stock superduty leaves would be, hopefully cheap. Only if they would work, of course. why won't they work in the rear?
Laughing Gas
Joined: Nov 2003
Posts: 904
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From: PHOENIX
Originally Posted by Tre-E_Ford
I had heard that rears would work. I'll see how much they are. There's a superduty shop SDHQ, and i wanted to see how much stock superduty leaves would be, hopefully cheap.
They only had 50 miles on em.(distance from dealer to 4wheel parts wholesaler to my driveway)
Keep your eyes peeled there or call your local 4wheel parts shops. They should have plenty of stock take offs.
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Senior User
Joined: Jan 2008
Posts: 439
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From: Yuma, AZ
I'll give my local shop a call. Its called Super Duty HeadQuarters. They should have some or they don't live up to there names. If i can get some than i'll try it out. What about the ubolts? Do i use stock hardware?
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Laughing Gas
Joined: Nov 2003
Posts: 904
Likes: 0
From: PHOENIX
Originally Posted by Tre-E_Ford
I'll give my local shop a call. Its called Super Duty HeadQuarters. They should have some or they don't live up to there names. If i can get some than i'll try it out. What about the ubolts? Do i use stock hardware?
Post Fiend
Joined: Jul 2006
Posts: 6,948
Likes: 44
Originally Posted by dirtyoffroad
the front eye on on the front superduty springs is 18mm,on my 78,I drilled the mounts to 23/32" for that size,is very close.The rear of the spring is 5/8"
Good call.
I used a 3/4" front bolt in my latest swap. Required a little work to the bushing itself, but worked the best so far well.
For previous installs, I used a steel bushing that I machined to make up the difference so I could use matching hardware front and rear, but the larger bolt worked out the best.
Good idea to keep these tolerances tight so the spring cant move. Spring bolts can't ever be big enough. Lots of load on these things.