Shackle Flip & Shock Question

[stoprez2006]

Good evening ya'll! I hope I am posting this in the right section and apologize if its not.

I am in the planning and buying stage of an SAS for my 1994 K2500 Suburban. I am going to run an 05+ Super Duty front axle using WFO radius arms in the front and a shackle flip in the rear.

I have tried searching several forums and the rest of Google and am coming up empty handed when it comes to rear shocks. Unfortunately, I am deployed and unable to get out to my truck for measurements, which is where I could use help from your knowledge bases.

When it comes to rear shocks, I'm planning on King 2.5 shocks to match the 2.5 King coil overs I have for the front. I am planning on a 4" shackle flip, stock length shackle, and stock rear springs. Given this configuration, what is the average shock stroke required? Any input you can provide is sincerely appreciated!

 

[ZRoe]

First of all, Thank you for your service.

I'm actually sorting out a shackle flip right now. My truck came with 8 leaves plus the overloaf in the rear leaf pack and rode pretty stuff so I figured I would pull out the add a leaves and do a shackle flip.
I netted more lift than desired and need to install some junkyard leaf springs to make sure I'm not fighting with a lifted leaf pack.

When it was Leveled to the front 6" subframe lift the typical lifted rear shocks that max out at ~30" are fine but with the shackle flip there is a lot more droop available with my existing leaf pack needing 32" of extension on the shock mounted to the rear of the axle (driver side) since the axle also moved forward during the shackle flip.

Hope this helps. I'll post up some more measurements once I get the known factory leaf springs bolted up and check for travel.

Really interested to see your build, and stay safe over there.

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[stoprez2006]

Thank you for the info! Have you already swapped out the leaf springs and if so, how many leaves are in the new pack? The 32" extended length is very interesting. I recently talked to Poly Performance to see if they could give any insight to travel, diameter, and valving required and they did recommend a 2.5x12 shock. King shocks meeting this spec are 32.650" extended and 20.650" compressed. Do you think the factory leaf pack with a shackle flip would use 12" of travel?

 

[ZRoe]

I don't have the stock springs on yet, and I have been having a tough time getting the leaf springs that are on it to flex. Best I could get with a jack was 1.5" of compression from ride height (this is probably a combination of my method and the possibility of having a lift spring currently installed). From ride height I get almost 6" of droop.

I think the reason for the 12" is more about overall length than total travel.

I'll post more about my shackle flip when I can spend some time at a computer.

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[ZRoe]

Turns out Mr. previous owner had actually put lift springs on the truck and then added 3 more add a leaves for some peculiar reason. So now I need to clean up the JY leaf springs I got and see how it sits on those.

Let me know if you are interested in the lift springs. They actually rode pretty nice once I got the add a leaves out.

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[stoprez2006]

How much lift do you figure is built into those?