K10/K20 frame

[Blue Ox]

So it sounds like K10 and K20 frames are actually a lot different then. (And what "manuals" stated this, btw? I'd be interested to read it.) A lot of bad info floating around then it seems. An no, there is no "indication on the frame" of where the mount would go. I'd just have to measure 4" back from the current holes.

www.gmheritagecenter.com

You can download the specs for your year truck and compare. It will give you material specs and frame modulus for the different trucks. i.e. my '85 K20 with the heavy duty C6P spec uses the same gauge frame material as a 30 but with the frame height of a 20. So, a 20 but different. Interesting reading if you have time to kill.

 

[eskimomann209]

I would be very reluctant to say they’re the same also. You’re probably reading threads that are discussing body swaps. In this case the frame would be the same for that purpose. But for strength and mounting locations for suspension. I would assume there are differences. Subtle. But still different. But as mentioned there might very well be dimples in the frame at either location. GM was known to use and reuse and multi purpose as much as they could.

 

[SquareRoot]

I don't buy a 10 frame is the same as a 20.
That sounds ridiculous.

X2

 

[bucket]

I don't think there is a "standard" answer regarding the 10/20 frames. It probably varies for every year. I know at some point, the K10 frame was thicker than C10 and similar to K20. But that might have been just in the later years.

 

[Jalopy_J]

www.gmheritagecenter.com

You can download the specs for your year truck and compare. It will give you material specs and frame modulus for the different trucks. i.e. my '85 K20 with the heavy duty C6P spec uses the same gauge frame material as a 30 but with the frame height of a 20. So, a 20 but different. Interesting reading if you have time to kill.

Oh, I've spent a lot of time looking at those. I hate how they are missing most of the pages though. I'd never noticed frame modulous in them though. It appears regular cab K10 and K20 have the same frame thickness unless it was the C6P offered in later years, like yours, which has a thicker frame, and shortbed trucks were slightly thinner. I'd be more curious to know what years K10s had both sets of holes in them though.

 

[Jalopy_J]

https://www.gmsquarebody.com/threads/revisiting-k10-vs-k20-vs-k30-frame-specs.11279/

I found an old thread I hadn't seen yet, where a member has figured it all out. That thread should be stickied. I also have a feeling the frame changes that came in 1980 is when both sets of holes were probably added to K10s.

 

[bucket]

https://www.gmsquarebody.com/threads/revisiting-k10-vs-k20-vs-k30-frame-specs.11279/

I found an old thread I hadn't seen yet, where a member has figured it all out. That thread should be stickied. I also have a feeling the frame changes that came in 1980 is when both sets of holes were probably added to K10s.

Cool! I don't remember that one.

I'll go double check, but I believe my '78 C20 Burb has the C6P option. But maybe also, trucks were different.

 

[IndianCountry]

so what im wondering is, on the suburbans the k20 frame, is the frame rails at least bigger? as in the circumference of the C channel? the heritage center manual said the k20 burb frame had a bigger "section module" than the k10

oh yeah and specific year 84 k20 suburban diesel

 

[bucket]

so what im wondering is, on the suburbans the k20 frame, is the frame rails at least bigger? as in the circumference of the C channel? the heritage center manual said the k20 burb frame had a bigger "section module" than the k10

oh yeah and specific year 84 k20 suburban diesel

It simply means that the steel is thicker.

 

[pontiac6269]

My 81 C20 frame is 3 mm thicker then a 80s K10 frame I cut the front spring perches off of. The 81 C20 frame is also the thicker then the 79 K20 frame I have. The C20 also has the 56" rear springs.

 

[AuroraGirl]

I can tell you tomorrow what springs my 3/4 ton has and if it has the holes in the morning, if I remember to look.

 

[C10MixMaster]

Yes, all three of my K-Burbs have had the holes in the frame for both spring lengths. I'm pretty sure many trucks did too, but I don't currently have one so I won't guarantee it.

My c10 has both sets of holes and came with the 56" springs.

 

[AuroraGirl]

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[bucket]

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Yep, holes for both lengths. Also, your main leaf appears to be broken?

 

[AuroraGirl]

Yes. Its broken in two places. Just the driver side. Its a plow truck on property. Before my grandfather died he had another one, presumably from a junked truck, laying in the shed. Its heavy as hell but I figure if I get it on the road I will fix it.