Shackle Flip™ Kit for '67-up GM Trucks
As seen in
Petersen’s 4WOR, 4X4 Power, Off-Road.com and
ColoradoK5.com. Turns the
factory rear tension shackle into a compression shackle for 2
1/2 or 4 inches of lift without using blocks. Bolts to factory
holes with Grade 8 hardware for a stronger than stock mounting
system. We also carry stock length u-bolts for
installations replacing lift blocks. Check the notes below
for details on the Ultimate Adventure K10 rear suspension using
our 2.5" shackle flip kit.
How many of you want to get rid of your rear blocks? Due to
popular demand, we’ve developed this kit to eliminate rear
Our brackets bolt to the frame in the factory spring hanger holes and
"flip" your factory tension shackle over to a compression
shackle. The kits give four inches of lift so they allow you to
use stock springs for a 4" lift, 2 inch springs for a six inch
lift and so on.
Eliminating lift blocks helps reduce axle wrap and using flatter
springs gives better ride quality and suspension flexibility.
This kit is extremely durable with fully welded, ¼" gusseted
brackets and all grade 8 mounting hardware. We even moved
the mounting point forward to give you a better shackle angle.
That’s why the brackets don’t look "straight". We now have
available a kit to lift your '73-'87 truck or 73-91 K5/Sub 2
Please note: Blazers,Suburbans and some 1-ton trucks
had straight front axles through the 1991 model year. They will
use the same kit as a '73-'87 of the same duty level.
recommend using our 4" shackle flip with our 6" Super Shackles,
see explanation on that below**
installation reviews check out these links:
Shackle flip install by ColoradoK5.com
Shackle flip install by Off-Road.com
'73 to '87 K10 & K20 & '73 to '91 K5/Suburban 4" Lift
$189.00 Buy Now
'87 K10 & K20 & '73 to '91 K5/Suburban 2 1/2" Lift
$189.00 Buy Now
1-ton 4" lift
*This kit is for K30 1 tons only, not for a 1/2 or 3/4
ton truck with a 1 ton axle*
$189.00 Buy Now
GM 1-ton 2 1/2" lift
*This kit is for K30 1 tons only, not for a 1/2 or
3/4 ton truck with a 1 ton axle*
$189.00 Buy Now
‘67-’72 GM 4" lift only
$167.00 Buy Now
‘88-'98 GM 1500, 2500 and 3500
Pickups 4" lift only
and '92-99 2500 Suburban with drilling required)
1500 Suburban only, 4" lift
2500HD and 3500 series GM 4" lift only
$195.00 Buy Now
'99-06 1500 and 2500 Pickups 4"
parts you may want to consider with the shackle flip kit are:
HD Rear Super Shackles
Greasable rear bushing kits
have 8" rear springs you need to use our 2.5" shackle flip
and 6" long shackles. This still gives the same 4"
lift height and the extra shackle length will keep the
shackles from flipping forward or back when the deeper arch
spring extends under load.
DO fit trucks with 56" rear leafs. The brackets are the
same, and will mount directly in place of your existing
Installation of the shackle flip kit requires removing the
rivets from the factory frame brackets by air chisel,
grinder, or your favorite other method. At that point, the
holes are drilled to clear the bolts and the brackets are
bolted on. This will most likely require removing the
dropping the gas tank down on Blazers and Subs for access to
the bolts. We've had good luck just hinging the tank
on it's mounts so we don't have to disconnect the wires and
angle is a common question with this kit. The quick
and easy answer is that there is no quick and easy answer.
Proper pinion angle depends on drivetrain length, wheelbase,
gears, tires, vehicle speed and more. It usually boils
down to what works for your truck. In general, the shackle
flip sets the pinion angle about right for most 4" to 6"
lift Blazers and shortbeds, especially the later models with
the aluminum transfer cases. Longbeds and Suburbans
will probably (but not always) need to shim the pinion down
a few degrees for best driveshaft alignment. If you
have questions about how to set up driveshaft angles, visit
That's Tom Wood's Custom Driveshafts website and has a good
tech section with info on setting driveshaft angles.
wonder why we don't have a Shackle Flip kit for more than 4"
of lift. The reason is that to gain more lift, the end
of the spring has to drop down twice the desired lift
amount. In other words to gain 1 extra inch, we would
have to drop the rear of the spring a full 2 inches.
This drop at the tail of the spring can become a ground
clearance problem and promotes roll-oversteer which is a
handling problem in which the rear of the truck starts to
feel "loose" under hard cornering with body roll.
We've chosen the 4" lift height as the limit for these
reasons and this is also why we typically don't use our 4"
shackle flip with our 6" Super Shackles.
carrying ability is also a common question. Basically,
if you keep the factory overloads, you won’t have any
trouble. We've designed the shackle angle to retain as
much load carrying ability as possible with a lifted 4wd.
no more lateral lateral motion of the vehicle than with the
stock tension shackle bushing setup. It may look as if the
axle could move side to side easier, but the only thing that
puts more leverage on the bushings is the additional ride
height, which you also gain with blocks or lift springs.
trucks require a different flip kit than k5's, k10's and
k20's. The kit is the same price, we just need to know it's
for a 1-ton when you order it. The difference is that the
spring center spacing on the 1-ton axle is only 40 1/2", and
on the rest of the trucks, it's 42 1/2". The brackets are a
different shape to reflect that.
Looking to install
longer rear springs on your truck? 56" GM springs and the
'88-up 64" GM springs are becoming more popular to swap in
due to the increased flexability and ride quality. You can
use our Shackle Flip for the shackle hanger by putting the
brackets on the "wrong" side of the truck to move the
mounting point back and/or re-drill the frame to bolt the
brackets on wherever you need them. Also check out our
longer HD rear shackles for use with longer springs.
Adventure K10 used our 2.5"
shackle flip with a custom 5" shackle (since we weren't in
production on our 6" HD shackles yet) and a '88-98 1/2T
truck spring. The front spring hanger was moved forward
about 6" and the shackle flip was moved back about 5" to
accomodate the extra 12" in length over the original
springs. This created a simple, durable and flexible
suspension that worked great on the varied terrain of the
category you would like more information on.