🛠️ Squarebody Chevy Suspension Guide (1973–1987 C/K-Series)

When it comes to building a Squarebody that rides right and performs better than factory, your suspension is the first system to rework. Whether you're cruising a C10 or building a trail-tackling K20, understanding how these trucks were set up — and how to improve that setup — is key to ride quality, axle geometry, and long-term performance.

This guide breaks down the stock suspension system for both 2WD and 4WD Squarebody Chevys, then walks you through modern aftermarket solutions — including a fully adjustable CFM Industries suspension system we offer exclusively at Blazin’ Biddles’ Off-Road.

🔧 Stock Suspension Overview (1973–1987 Squarebodies)

➤ Factory Leaf Spring Setup (4WD Trucks – K10, K20, K30)

  • Front: 2.5" wide leaf springs, typically 47"–48" long
  • Rear: 2.5" wide springs, typically 52" or 56" depending on model/tow rating
  • Shackles: Factory shackle points upward (from frame to spring eye)
  • Shock Mounts: Conventional tube shocks on axle or trailing arm
  • Design Issues:
  • Poor ride quality due to short leaf length and poor shackle angle
  • Factory shackle angle is nearly vertical, reducing flex and causing bind
  • No adjustability in axle position or pinion angle

➤ Factory Coil Spring Setup (2WD C10s)

  • Front: Coil springs with stamped steel control arms
  • Rear: Coil springs and trailing arms (or leafs on some heavier-duty models)
  • Design Strengths:
  • Better ride quality than leafs
  • Good base for lowering or air suspension conversions
  • Limitations:
  • No caster or camber adjustability in stock form
  • Soft rates under load, limited travel for lifted use

⚠️ The Shackle Problem

Factory shackle angle is one of the biggest ride quality killers in a lifted Squarebody. With the shackle mounted nearly straight up and down, the suspension can’t properly cycle. Instead of smoothly flexing, it binds.

When you lift a truck without correcting shackle geometry, you also push the axle forward or backward — depending on how you add height (blocks, longer shackles, spring packs). This misalignment affects steering, pinion angle, and leaf spring function.

🔩 CFM Industries Adjustable Suspension System

Exclusively at Blazin’ Biddles’ Off-Road

We’ve partnered with CFM Industries to offer a suspension system that finally solves this problem — not just with height, but with geometry control. If you want your lifted Squarebody to drive and flex the way it should, this is the package to get.

✅ What’s Included in the Package:

  • Adjustable Front Spring Hangers
  • Bolt-on design, stronger than factory
  • Allows axle relocation and shackle angle tuning
  • Compatible with 52" front springs for better ride and flex
  • Adjustable Rear Spring Hangers
  • Sets correct angle for rear leaf spring and pinion alignment
  • Compensates for shackle flip offset
  • Shackle Flip Kit
  • Flips rear shackle mount below the frame
  • Improves ride quality
  • Adds 2.5"–4" lift depending on spring setup
  • Corrects vertical shackle angle to 30–45 degrees (ideal for flex)
  • Optional Springs
  • We’ll help match front and rear spring length and rate to your setup
  • Compatible with 52", 56", and longer custom leafs

📌 Why You Need It

When you lift a Squarebody the traditional way, your axle usually ends up too far forward (especially in the rear with a shackle flip). This leads to:

  • Poor shackle angle
  • Driveshaft binding
  • Off-center axle alignment

With our CFM package:

  • You set your shackle angle correctly
  • Adjust your axle forward or backward
  • Improve ride quality and articulation

This is the only Squarebody suspension system designed for full adjustability, trail performance, and bolt-in simplicity.

View Kit and Options

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Let your customers know they can:

  • Select spring options
  • Request 52" front spring compatibility
  • Get install support directly from Blazin’ Biddles’ Off-Road

🔧 Suspension Geometry Tips

  • Shackle Angle Rule of Thumb:
  • Ideal angle is 30–45° (leaning rearward at ride height)
  • Too steep (vertical) = harsh ride, poor articulation
  • Too flat = excessive flex, axle walk
  • Axle Relocation:
  • Common issue with non-adjustable shackle flip kits
  • Our system allows you to dial in where your axle sits — crucial for driveshaft alignment and bump-stop contact

🚘 2WD Suspension Options – Lowering & Air Ride

Lowering a 2WD C10? You’ve got more options than ever. Here's a breakdown of top kits and pricing as of now:

🔽 Static Drop Kits

BrandDrop (inches)Components IncludedPrice RangeBelltech2–4 front / 4–6 rearSpindles, coils, flip kit$450–$800McGaughys2–5 front / 4–7 rearSpindles, shackles, flip kit$500–$850Western ChassisSimilar kitsHigh-quality drop components$600–$900


💨 Air Ride Systems

BrandTypePrice RangeNotesRideTechFull Air Suspension$2,600–$4,500HQ Series shocks, bolt-on kitsChoppin’ Block / GSI / KP ComponentsCustom/Universal$1,800–$5,000+Great for bagged trucks/show builds



Most lowering kits include either a flip kit, drop spindles, or control arm swap depending on drop amount. RideTech’s systems include air management and control arms.

🧰 Other Lift Options for 4WD

If you're not ready for full adjustability but still want to lift:

BrandLift TypeLift HeightPrice RangeSkyjackerSpring lift kits2.5–6"$750–$1,200Tuff CountrySpring lifts2.5–4"$600–$1,100Offroad DesignShackle flip kits2.5–4"$300–$500


⚠️ These kits don't fix geometry or shackle angle unless paired with adjustable components — that's where our CFM system stands apart.


Whether you’re looking for the perfect ride height or serious off-road flex, your Squarebody’s suspension starts with the right geometry. Poor shackle angle, stiff short leafs, and generic lift kits just won’t cut it anymore.

With our fully adjustable CFM Industries Suspension Package, you can set your truck up the way GM should’ve done it — with correct shackle angle, axle alignment, and ride quality that matches your build goals.

For full suspension tech, product support, and setups that actually work — stick with Blazin’ Biddles’ Off-Road.