1/2 vs. 3/4 ton leaf spring differences

[BigRed76]

I'm in the process of converting a K10 chassis to K20 for my '70. I've done some searching and haven't found much info specific to 67-72 4wd springs. Basically I'd like to know the difference of leafs between 1/2 ton and 3/4 ton springs on 4wds.

I will be lifting the truck 2" with Tuff Country EZ-Ride springs in the front, and was thinking about going with 2" blocks in the rear, but I don't want to use 1/2 springs in the rear. Tuff country lists the same part #'s for springs for 1/2 ton and 3/4 ton, not sure what's up with that

My current 1/2 ton springs have 2 leafs up front, and 4 leafs plus an overload leaf out back. And I have a set of rear leafs from a 2wd 3/4 ton, which have 5 leafs plus an overload leaf, but they are only 2.25" wide.

[Bigdav160]

I'm installing the same kit on my K20 right now. I almost asked the same questions as I wasn't sure of my current setup (stock or not) and the possibility of needing the HD Tuff Country springs. Right now I'm glad I went with the 2" EZ ride.

My SPID list HD Front spring as an option. It had four leaves in front. The rear had five leaves plus the short overload on the bottom and a 2 inch blocks.

Note the new rear springs have the correct EZ part number but say 4" on the tag. The truck sits up quite a but higher than before.

[BigRed76]

That's interesting, I'd never heard of the HD front spring option for a 4wd. How do the EZ ride springs actually ride?
Posted via Mobile Device

[BigRed76]

I'm thinking that the stock 3/4 tons had 3 leafs in the front and 5 leafs in the back. Can anyone confirm this?
Posted via Mobile Device

[Bigdav160]

Originally Posted by BigRed76

That's interesting, I'd never heard of the HD front spring option for a 4wd. How do the EZ ride springs actually ride?

I haven't driven it yet. I still have to install the shocks and weld in the rear spring perchs.

I went this route because the PO installed a 14 bolt and welded the perches so the pinion was pointed up at a 30º angle. I knew I was going to have to cut that out and correct it. I also had a broken leaf on the RR and a broken centering bolt in the LF.

[BigRed76]

Originally Posted by Bigdav160

I haven't driven it yet. I still have to install the shocks and weld in the rear spring perchs.

I went this route because the PO installed a 14 bolt and welded the perches so the pinion was pointed up at a 30º angle. I knew I was going to have to cut that out and correct it. I also had a broken leaf on the RR and a broken centering bolt in the LF.

Ah I understand. You'll have to let me know how the ride is. Mine is still a long ways away from being driven.
Posted via Mobile Device

[BigRed76]

Anybody with a stock K20 have some input on this?
Posted via Mobile Device

[Stocker]

I've been gone for a few days and just now saw this thread.... The OEM front springs on my '72 K20 were two leafs (since replaced with 2.5" Skyjacker Softrides). Rear springs are 5 leafs. It's a light-duty K20, can't recall for sure but seems like 6800# GVWR -- door tag got painted over.

[Bigdav160]

Interesting. My GVWR is #7500

I did take my Suburban out for a spin and here's my impression of the Tuff Country 2" EZ ride. I went with their 8000 series gas charged shocks

Firmer than stock. It can be harsh over larger bumps (at speed) but on smooth pavement it was a pleasure to drive.

On the down side my ride height is still 1 1/4" low in the rear. I'm going to make some taller perches today and correct it. I have an inch extra in the rear U-bolts to make it happen.

[BigRed76]

Originally Posted by Bigdav160

Interesting. My GVWR is #7500

I did take my Suburban out for a spin and here's my impression of the Tuff Country 2" EZ ride. I went with their 8000 series gas charged shocks

Firmer than stock. It can be harsh over larger bumps (at speed) but on smooth pavement it was a pleasure to drive.

On the down side my ride height is still 1 1/4" low in the rear. I'm going to make some taller perches today and correct it. I have an inch extra in the rear U-bolts to make it happen.

That's interesting that it rides stiffer than your HD front springs
Posted via Mobile Device

[med.bronze]

Originally Posted by BigRed76

Anybody with a stock K20 have some input on this?
Posted via Mobile Device

I used to own a 71 K20 and like Stocker's mine had two in front and five in back
Posted via Mobile Device

[cmhamilton68]

Would anyone be able to tell me the distance between the axle tube and frame front and rear on a stock k20??
Thanks

[Stocker]

Originally Posted by cmhamilton68

Would anyone be able to tell me the distance between the axle tube and frame front and rear on a stock k20??
Thanks

Rear spring is ~52" long eye to eye. IIRC, the axle is located at the center.

[BigRed76]

The GVWR on mine is 7500, and it was 2wd. I'm starting to think I wanna track down some stock 3/4 ton springs rather than buying lift springs. My front springs have 2 leafs, but I'm not sure if they're any different since they're from a half ton, and they sag pretty bad.

[Bigdav160]

Here's a snapshot of the parts book for front leaf springs. There are many choices in part number but not that many choices of the number of leaves. It appears, 1/2 and 3/4 ton could share the same springs.

[BigRed76]

Originally Posted by Bigdav160

Here's a snapshot of the parts book for front leaf springs. There are many choices in part number but not that many choices of the number of leaves. It appears, 1/2 and 3/4 ton could share the same springs.

Thanks for sharing that. Interesting that the 3 leaf front springs are HD springs and there's no mention of 4 leaves. Would you mind showing the same info for the rear springs?
Posted via Mobile Device

[Bigdav160]

I'm not sure I've got it all.

[BigRed76]

Thanks for getting me those, that's great info. to have. I think I'll be going with my original plan of a 2" lift, since I'll need the extra clearance up front to move the big block forward 2".

[reuserm@yahoo.com]

i have a 72" 1/2 ton shorty with 402 and leafs, is this an odd truck?

[reuserm@yahoo.com]

forgot to mention, i have complete coil suspension to put in truck so ? is, should i or leave original.