Correct Shocks for a K20 "71???
 

OK the PO told me that the truck had a 3-4" lift. Currently the truck has Rancho 9001 & 9112 installed. I purchased RS 5001 and RS 5112 (which is the correct sub for the 9000's). The distance from the front rubber bumber is 3.5" and the shock measurement is 16.5" (CP to CP). The rear is 5.75" and is resting at 19.75". The tech at Rancho thought I might need the 5151 & 5118, because he thinks I have maybe a 2" lift!!! So before I try to return these shocks, how and where do I tell what size lift I have?

Re: Correct Shocks for a K20 "71???
 

do you have body spacers?
look for + arch in front spring, OE - arch.
2" lift? do they even make a suspension lift like that?
is there more shock shaft exposed than travel available? cuz that's what ya want
what's wrong w/ 9000's? got receipt Rancho will warranty.
put a ziptie around shock shaft & test drive & see where ziptie has moved up to.
cheap easy travel indicator
dont forget your shock droop like when jacked up or as 1 tire goes in hole for full travel available.

Re: Correct Shocks for a K20 "71???
 

No receipt 2nd owner, so no warranty. I just turned them all the way to 9 and it did take out some of the chatter bounce. The tech was concerned that the shocks were to close to bottoming out. I don't see any lift arms at all. It looks OEM to me. I'm running 255 85r 16 (~32x10) and there is plenty of clearance in the wheel wells. That's a lot big than the original tires

Re: Correct Shocks for a K20 "71???
 

Years ago I installed Softride 2" front springs (and longer KYB shocks). I took some measurements at the time, and just found that piece of paper.

With the truck on level ground, it was 3 3/4" to the bump stops, and the shocks were 17" eye-to-eye.

Very close to your measurements, so yeah, you probably have a 2" lift. All other steering hardware etc. can remain OEM with 2".

Re: Correct Shocks for a K20 "71???
 

I have a Rancho 4" lift system on my 72 3/4T truck that consists of front springs, rear blocks and RS5000 shocks, (2 5001 & 2 5112) and a 4" drop pitman arm. My stock springs had almost a reversed arch to them, my Rancho springs have a pretty pronounced arch.

If it helps i can rake some pic's of the springs and a comparison shot of my stock pitman verses the 4" droped one.. then measure my center mount to center mount distances so you can check them against your truck.

Found my recipt and my front springs are #41054S
http://www.eraceware.com/rancho-4105...a65578853a8c0d

Re: Correct Shocks for a K20 "71???
 

That would help. I'll take some pics after work and then compare.

Re: Correct Shocks for a K20 "71???
 

Heres some pics altho some didn't turn out too well. The distance from the front bump stop to the flat on the spring cap is somwhere between 4 3/4 to 5" depending on the angle ya look at it, i couldn't fire it up and turn the wheel to get a better shot.

Re: Correct Shocks for a K20 "71???
 

Heres a couple more, also keep in mind my bed is off the truck at the moment, measurement is straight down to axle....

Re: Correct Shocks for a K20 "71???
 

Finally got around to calling the tech support at Rancho. The PO was wrong about the lift and he had put the wrong shocks in (too long). I returned and got the correct ones, 5151 and 5118. She rides a lot better. I can't wait to see how she will handle off road, seeing how the old shocks were bottoming out!!!

Re: Correct Shocks for a K20 "71???
 

Thanks for the update... glad to hear you got it all figured out!! :chevy: