Rear spring ID.... Oddball??

[Permafrost]

Maybe some of you with a little more experience in the 67-72 trucks can chime in here.

My '68 K10 has a two-leaf rear spring packs. I'll have to say I've never seen that before. My guess is it's an aftermarket spring assy? The truck is stock height.
The truck is a future project and not a driver so I cannot say how they perform, other than they don't give much when my fat-arse bounces on the rear bumper.



What do you folks think..?




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[Chevy1TonFun]

I believe I have seen this question pop up before. If remember correctly the answer that was giving was that this was a factory option.

[DirtyLarry]

Those are odd on that old of a truck. They look like Parabolic springs rather than tapered leaf springs. Parabolic springs is what most of the new trucks run where they have a few fat springs instead of a big stack of thin tapered leafs. I had no idea they had them way back then.


....actually, the more I look at them, they look like parabolics off the front of a Ford Super Duty. How long have you had this truck?

[lowrollin70gmc]

Those look identical to the ones on the back of my 68 k20 burb that I believe are stock, but so much has changed on mine I have no clue.

[Permafrost]

Larry,
My first reaction was they were some type of front spring swapped in; however they appear they have been there awhile. I've only owned the truck since August. It's been setting years; a title search in my state indicated it was never registered here and the last registration in the glovebox was '76 in Cali.

Ridin',
There is no mention of rear spring option on the SPID, doesn't mean it wasn't a dealer option though...? I don't know how detailed the SPID's got too?

Lowrollin,
Interesting, maybe they aren't afermarket...?

Here's a pic of the truck for you pic-hounds...




Thanks!


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[special-K]

I've never seen that on one of these before. Any spring option would be listed. I love those front tires. Are the 16" wheels listed on the SPID? They were an option. are those tow hooks round stock,like the later ones? Makes me think someone did some tweaking on this thing at one point. Is the front axle an open knuckle? Those lock-outs look later than would be on a pre-70 axle.

[Permafrost]

Special-K,

Only springs listed on the SPID is HD Front Springs.

I dig the tires too; sadly only the fronts match and they are bias tube-type caps and the casings are shot. The front wheels are an early wheel with the center cap clips similar to what was on my '50 GMC.

The tow hooks are round to square and they aren't listed on the SPID. I'm sure some one added them.

Front axle is a closed knuckle and there is a receipt in the glovebox for Warn hubs dated 3-21-74


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[morgan71]

Yep those are factory, my 1968 3/4 ton 4x4 had the same springs before I swapped them for some that I had made. You have probably also noticed that the spring is 2.5 inches wide at the spring perch and it tapers out to 3 inches at the ends. Spring guy told me that was the way it was done back then. They also get thinner at the ends. Mine had sagged quite a bit so I had new ones made up cause you cant buy rear lift springs for 67-68

[KrazyRay]

Those are stock springs for 1968.

[lowrollin70gmc]

Digging this one up for some more knowledge.

I have these in the rear of my 68 k20 burb and am wondering if adding a leaf from a donor truck (probably my 91 Dodge w250 engine donor) would be a bad idea for about 1-2" of lift. I'm going to do a shackle flip for my first 4" (replacing the current block) and want about another 1-2 to pull some sag out of the rear and clear 37s with trimming.

Any advice?

[72longbed]

Those rear springs have sagged, unless there is weight in there at the time of the pic? That truck sat higher in the rear when new if it is a factory 4x4.

I'd either have them re-arched or Add-A-Leaf helper under the pack.

72

[V6GMC]

those are stock I had the same one's on my 1968 GMC K1500

[fp1967]

Every 67-68 4WD that I've seen has had these springs, 2 leafs per side on a K10 and 3 on a K20.

[msgross]

My 68 K-10 had 2 leafs on the rear, I added a short add-a-leaf to firm it up and raise the height a little.

[First c10]

So is the blocks under the rear leafs stock? If so how thick are they?
My 68 has 44" eye to eye in the front and 57" eye to eye in the rear and the axle looks to be spcentered in the leaf 28x28 from what I can measure with a tape measure. But I never noticed if my truck had the blocks.
What is the rear eye to eye measurement on a 69-72 k10 leaf mounts?

[msgross]

The springs are original, someone might have added the blocks and new ubolts in the past to correct for a saggy rear end. The mirrors aren't original so it a chance that things have changed over the years. I don't have any good pics of mine before I took it apart but I can take some measurements if needed.

I had an "HD spring option" on mine but that's an extra leaf up front, no blocks anywhere.

Those tow hooks are original, don't lose them.