Anyone swapped front leaf springs on a K-series from 2-leaf to the 3-4 leaf pack

[thefarmboy21]

So I finally picked up a sweet set of vintage Mag Slot wheels for my K20. So before I put them on I want to go ahead and get the front end another 2" in the air. I want to know the best way to do this. Particularly I want to know if anyone knows how much height there is to gain from swapping out the stock saggy 2-leaf packs and swapping in factory replacement 3 leaf or 4 leaf packs. I'm wanting to gain roughly 2" in the front. I'd like it to sit basically like a K-30 when it was new. I know I could just get 2-2.5" lift springs, but I can new springs from General Spring for quite a bit cheaper and they'll ligive me the same effect. What I don't want is it to feel like I shoved metal pipe inplace of the shocks and rattle all the glass out of the truck and pick the front wheel up if I get it in some ruts. Just looking for the most practical route for an occasionally driven family heirloom/farm truck. Thanks.

[VileZambonie]

So is it stock height now? If so do an add-a leaf. If you want a cush ride with a lifted K20... LOL Better open up the wallet and ditch the leaf spring suspension

[thefarmboy21]

Hahaha, no I don't want a "Cush ride" but I was afraid if I swapped in factory big block, one-ton 4-leaf springs, that it wouldn't have any give whatsoever. Add-a-leaf kits are $99. I can buy new 4" lift springs for $100 each with bushings. I can get factory 3-leaf packs for $80 and factory 4-leafs for $104. The obvious choice for most would be buy the 4" springs but I seriously only want to gain about 2-3" up front and adjust the rear accordingly with a short block. Yes add-a-leaf kits would do that the cheapest, but I'll still have rusty worn springs with worn bushings....by the time I buy new bushings and take apart, clean and paint the front springs and add the helper springs.....it won't have been worth saving the $100.

[VileZambonie]

You're splitting hairs at that point so just take the $ out of the equation. It sounds like you want new springs so get new springs. You can buy the 2.5" spring lift kit.

[thefarmboy21]

Well I guess more than anything I'm trying to find out how much height I'd gain from swapping in 3 or 4-leaf spring packs up front.

[thefarmboy21]

With my stock 30 year old 2-leaf spring pack up front and a Small Block, the leafs are negative arched at least and inch, maybe more.

[1967KaiserM715]

With new stock leaves you'll only gain 2" at best, I would go for the 2" lift springs.


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[Irish_Alley]

i dont have the part number but i found a front add a leave that will add 1.5-2" lift on the stock set up and each spring has a rating for 500lbs so a total 1k lbs

[Greybeard]

Well I guess more than anything I'm trying to find out how much height I'd gain from swapping in 3 or 4-leaf spring packs up front.

Simple answer- figure out how thick the stock spring pack is at the perch, decide on how much sag is present (stock height is nominally with straight to slightly positive arched springs), figure approximate lift of the new (stock) springs by finding the thickness of the new springs at the perch and assuming they will ultimately be flat to slightly positive (with age) just like the OEM was, the advertised weight rating will determine the amount the spring deflects at rest so this will vary with the engine compartment contents. The difference will be the lift achieved. Nothing set in stone. 35+ year old spring will likely be sagging at least 3" from new. Especially if the spring eyes are below the perch level. Don't forget the spring pack adds fractions per leaf... 3/8" leaf adds 3/8", 1/2" leaf adds 1/2", etc. So going from the normal 2 leaf pack to a 3 or 4 leaf pack will only yield less than 1" in most cases.

I said simple answer- I lied, there really is no 'simple answer' for your situation/question. At best you can get close, but the caveat is that with spring height comes stiffness in most cases involving stock manufactured (styled) spring packs.

Now- aftermarket springs are a different animal, they are purpose built, although sold generically as a specified lift. For instance; a 4" lift can still yield between 3"-5" depending on engine compartment contents.

There is a lot of engineering that goes into a spring pack but the easy answer is that more leaves equal softer ride at the risk of sagging sooner. However, 'sooner' means decades most likely, not years. The reality is that these trucks will likely not be around for that long anymore as the end of their rebuildable lives are getting closer and closer. Sad but true. The rate of decay and destruction of these poor trucks is increasing at an exponential rate as the numbers of them dwindle.