Botello Dynamic Engineering (BDE) Systems LLC

Chevrolet Corvette C2 & C3 Rear Suspension Lowering 9" Bolt Kit (1963–1982)

Red Bushings | Complete 14-Piece Rear Kit | Install Guide | 2"-5" Adjustable Drop

Included in This Kit

• QTY (2) Grade 8 DIN 931 Metric Bolts — Custom 9" length for C2/C3 Corvette applications, finished in Yellow Zinc Chromate.
  Made in the USA.
• QTY (4) Grade 8 Oversized Washers — 1.73" OD with Yellow Zinc Chromate finish. Correctly sized for this application.
  Made in the USA.
• QTY (2) Grade 8 Steel Nyloc Locking Nuts with Flared Base — Yellow Zinc Chromate finish.
  Made in the USA.
• QTY (2) Volunteer Vette Products Rear Spring Mount Cups.
  Made in Tennessee, USA.
• QTY (4) Energy Suspension Rear Bushings (1 complete rear set) — Manufactured from Energy Suspension’s HYPERFLEX Performance Polyurethane.
  Style/Color: Low-Profile Red Bushings
  Made in the USA.
• QTY (1) Installation Instruction Pamphlet — Includes basic installation guidance with color photos.
• QTY (1) Packing Slip
• USPS Priority Mail Shipping Included — 2–3 Day USPS Priority Mail Service with tracking and insurance. Ships within 24-48hrs of order receipt.
  Available for USA customers only.

***International Customers Pay $34.99USD for Export/Import, VAT Fees, International Customs Paperwork, Tracking and Delivery***

If you’re reading this, chances are you’re not happy with the factory wheel gap on your C2 or C3 Corvette. At Botello Dynamic Engineering (BDE) Systems, we have extensive experience developing Corvette lowering solutions. Due to the success of our long-running and best-selling C4 and C5 lowering kits and brake upgrade kits, we are proud to now offer a dedicated lowering kit for 1963–1982 C2 and C3 Corvettes.

This kit was developed using Alex Retana’s 1969 C3 RestoMod Corvette, along with valuable feedback and testing from members of the CorvetteForum community. For enthusiasts who want improved stance and ride quality without the expense of a full custom coil-over or track suspension setup, our C2/C3 lowering kit delivers a clean, aggressive look while remaining affordable and practical for street use with a 2"-5" approximate adjustable range. 

One of the key advantages of this kit is that the ride height is fully adjustable to your preference. The included threaded lowering bolts allow you to fine-tune the rear suspension height as needed. During development, we tested both 9" and 10" bolt configurations. In our experience, 10" bolts could create clearance issues on some applications, potentially causing wheel or tire interference. After extensive testing, we determined that our custom 9" bolts provide the best overall fitment and performance for the majority of C2 and C3 Corvette owners.

However, if your setup requires a shorter or longer bolt, we can accommodate custom requests. Simply contact us prior to ordering. We maintain inventory and materials at our Ventura County office as well as through our Amazon.com LLC FBA warehouse.

In addition to customer and community testing, all BDE Systems products are tested on our own Corvettes, including:

• 1987 Corvette TPI — Modified
• 1994 Corvette LT1 — Modified
• 2003 Corvette Z06 — Modified
• C6 Z06 — Currently producing approximately 714 crank HP on E85

At BDE Systems, we are not just resellers or parts flippers looking for a quick sale. We build, test, and daily drive the products we sell because we are Corvette enthusiasts ourselves.

Strength Matters

BDE-Systems Lowering Bolts are engineered to meet the highest standards of strength and quality. Our bolts are rated Grade 8 / Metric Class 10.9 and comply with DIN 931 certification standards. In addition, the complete hardware kit provided by BDE-Systems LLC meets or exceeds Grade 8 requirements outlined by ASTM A324 Grade BD and SAE J429, ensuring exceptional durability, reliability, and performance.

This distinction matters because many competing kits use lower-grade Grade 5 hardware to reduce costs. Substituting Grade 5 hardware bypasses the engineering standards originally specified by GM and can compromise both vehicle integrity and personal safety.

Grade 5 hardware is intended for general-purpose applications such as household, carpentry, and low-stress use. It often lacks proper certification, traceability, and the tensile strength required for demanding automotive applications. Cheaper kits save money by using Grade 5, yet marketing as safe for use or "premium".

Grade 8 hardware, by comparison, undergoes rigorous testing and is specifically designed for high-load, high-stress environments. Trust General Motors Engineers, Trust BDE-Systems LLC Engineering and our thousands of customers running our kits worldwide.

Why Grade 8 Hardware Is Superior

• Higher Tensile Strength – Grade 8 fasteners withstand greater loads and resist failure under extreme stress.
• Higher Carbon Content – Increased carbon improves strength and hardness while reducing deformation.
• Enhanced Alloy Composition – Materials such as chromium and molybdenum improve fatigue resistance, durability, and structural integrity.
• Greater Durability – Designed to endure vibration, heat, and harsh driving conditions without compromising performance.
• Improved Safety – Stronger fasteners reduce the risk of failure, mechanical breakdown, or suspension damage.
• Industry Compliance – Grade 8 hardware conforms to strict ASTM and SAE standards for quality and consistency.

Many aftermarket kits use Grade 5 hardware—or worse—without disclosing the bolt classification. In most cases, these lower-cost materials are sourced cheaply and resold without proper engineering standards or testing.

BDE-Systems Standard and General Motors Standard

• Typical Aftermarket Hardware: Grade 5 or lower
• BDE-Systems Hardware: Grade 8 / Class 10.9 (matches OEM GM specifications)

Grade 8 bolts provide over 21% greater shear strength and 25% greater fatigue/tensile resistance compared to Grade 5 hardware. The same advantage applies when comparing Metric Class 8.8 to Class 10.9 bolts. Lower-grade hardware reaches elongation and fracture points significantly sooner under stress.

Since the 1950s, GM has used Class 10 / Grade 8 bolts in Corvette and rear suspension applications because of their proven reliability and strength. Every BDE-SYSTEMS LLC kit maintains the same hardware grade used by GM OEM applications, ensuring the highest standards of safety and performance.

Grade 5 Real-World Failures

Numerous CorvetteForum members have documented failures involving lower-grade suspension bolts. While you do not need to purchase from BDE-Systems, we strongly recommend ensuring any kit you buy uses true Grade 8 / Class 10.9 hardware only.

Reported failures include:

• CorvetteForum Senior Member “Greengear”
• CorvetteForum Senior Member “Kinkajou”
• CorvetteForum Senior Member “FR 73 454”
• CorvetteForum Senior Member “Danbo”
• CorvetteForum Senior Member “C5Natie” — including a serious highway accident caused by weaker rear suspension hardware failure

Adjustability Matters

BDE-Systems C2 & C3 Lowering Bolts provide an additional 2.80 inches of overall length compared to OEM spring bolts. This increased length creates a larger threaded adjustment range, allowing for easier compression and decompression of the rear suspension while offering substantial ride-height adjustability.

KIT PROVIDES 2-5" APPROXIMATE ADJUSTMENT - VARIES SLIGHTLY DUE TO SUSPENSION AGE, OPTIONS, SHOCK CONDITION AND CAR WEIGHT AS IT VARIES FROM 1963-1982 MODELS.

Through extensive testing, we determined that an 8-inch bolt limited available adjustment range and often positioned the nut at the very end of the threads. While a 10-inch bolt provided additional adjustment, certain aftermarket wheel and tire combinations could create clearance concerns due to variations in wheel offset, width, and suspension geometry.

After evaluating multiple configurations, we found that a 9-inch bolt offers the ideal balance between maximum adjustability and safe component clearance. It provides ample ride-height adjustment while maintaining proper distance from wheels and tires, even on many aftermarket wheel setups.

Need a different length? We stock shorter and longer bolt options and can substitute them into your kit at no additional charge. Simply contact us with your requirements.

Quality and Certification Matters

BDE-Systems LLC is an approved Amazon FBA Business Partner (2023) and maintains comprehensive Certificates of Conformance (CoC) and lot traceability records for the materials used in our products. These quality control measures have been part of our manufacturing process for many years and were independently reviewed during Amazon's approval process for our current FBA Business Account.

By maintaining CoC documentation and lot traceability records, we ensure accountability, consistency, and compliance with industry standards. These records provide verifiable proof of material quality and manufacturing integrity, reinforcing our commitment to delivering reliable, high-performance products. Amazon's review and approval of our quality documentation further demonstrates our adherence to rigorous quality control practices and operational standards.

When comparing lowering kits or suspension components, it is important to evaluate the transparency of the manufacturer regarding the material specifications, grade, and class of the hardware provided. Vendors that do not clearly identify their hardware specifications often utilize lower-grade alternatives, such as Grade 5 hardware. Choosing components built with properly certified Grade 8 hardware helps ensure the performance, durability, and safety of your vehicle.

To further enhance durability, all bolts, nuts, and washers included in our kits feature a yellow zinc chromate finish that exceeds OEM GM corrosion protection standards. Yellow zinc chromate is a chemical conversion coating applied over zinc plating that provides excellent corrosion resistance. This protective finish sacrifices itself before the underlying steel, helping prevent rust and extending the service life of the hardware in harsh environmental conditions.

Our C2 and C3 Corvette Bolt Lowering Kit combines premium components throughout, including:

• Grade 8 / Class 10.9 rear lowering bolts
• Volunteer Vette Products spring cups
• Grade 8 non-marring flanged nylon-lock nuts
• Grade 8 oversized washers
• Matching yellow zinc chromate corrosion-resistant hardware
• Hyper-Flex polyurethane bushings

The result is a lowering kit that delivers exceptional strength, corrosion resistance, durability, and long-term performance. We believe this combination of premium materials, certified hardware, and proven components makes it one of the highest-quality and best-performing C2 and C3 Corvette bolt lowering kits available on the market today.

Trusted Partnerships Complete the Package

Volunteer Vette Products

When replacing rear spring bolts, it only makes sense to replace worn spring hardware at the same time. That's why every kit includes a pair of C2-C3 Rear Spring Cushion Retainers manufactured by Volunteer Vette Products.

These retainers have been installed on hundreds of Corvette restorations and replacements and are designed as a direct-fit solution for worn or damaged OEM components.

By replacing these components during installation, you're completing the job correctly the first time and ensuring long-term reliability.

Energy Suspension Hyper-Flex® Polyurethane Low Profile Bushings

To complete our rear lowering kit, we've partnered with Energy Suspension, one of the most respected names in suspension technology.

Original rubber spring pads often become compressed, cracked, and deteriorated over time. This can contribute to squeaks, uneven ride height, and inconsistent suspension performance.

Replacing worn factory rubber pads with Energy Suspension's Hyper-Flex® Performance Polyurethane Bushings provides several advantages:

Benefits Include:

• Increased durability compared to factory rubber components
• Improved suspension consistency and longevity
• Enhanced vehicle stability during cornering, acceleration, and braking
• Reduced suspension deflection under load
• Improved traction and handling characteristics
• Manufactured from Energy Suspension's proven Hyper-Flex® polyurethane compound

Installing new bushings whenever the rear spring assembly is serviced is one of the smartest upgrades you can make for long-term performance and reliability.

Advantages of a Lowered and Adjustable Suspension

A properly lowered suspension can improve both appearance and performance by reducing the vehicle's center of gravity and optimizing weight transfer characteristics.

Reduced Body Roll

Lowering the vehicle generally reduces body roll during cornering, improving steering response and overall handling feel. A lower center of gravity helps the vehicle remain more stable during aggressive driving maneuvers.

Correcting Ride Height Variations

Many C2 and C3 Corvettes sit at different ride heights due to age, suspension wear, factory variations, and mileage. We've observed stock ride heights ranging from approximately 26 to 30 inches.

Our adjustable lowering kit allows owners to compensate for these differences and achieve a consistent, level stance.

Optimized Wheel-to-Fender Fitment

Aftermarket wheels often increase wheel gap and alter vehicle appearance. Adjustable ride height allows owners to fine-tune suspension settings to achieve the desired stance while maintaining functionality.

Whether you're running factory wheels or aftermarket combinations, our kit allows you to dial in the look and ride height that best suits your vehicle.

Improved Aerodynamics

Reducing ride height decreases the amount of air flowing beneath the vehicle, which can improve aerodynamic efficiency.

General Motors engineered Corvettes with a specific rake angle for high-speed stability. If your vehicle is used in high-performance applications, ride-height adjustments should be made carefully while monitoring handling characteristics.

For normal street and highway driving, adjusting ride height within the kit's intended range presents no concerns - Track users understand this more than anyone, and the kit can be adjusted and subjected to track needs.

Safety Matters

When purchasing suspension components, safety should always be the highest priority.

Important Recommendations:

• Purchase only from reputable manufacturers and suppliers.
• Never replace OEM Grade 8 suspension hardware with Grade 5, Class 8, unmarked, or unknown-grade hardware.
• Lower-tensile-strength fasteners will eventually fail under repeated loading and fatigue cycles.

Suspension hardware is subjected to constant stress, vibration, and cyclic loading. While lower-grade hardware may initially appear adequate, fatigue-related failures can occur over time, often under demanding driving conditions.

Most vehicle manufacturers, including General Motors, specify Grade 8 hardware for critical suspension applications because of its superior strength and durability.

BDE-Systems LLC exclusively supplies OEM-equivalent Grade 8 / Metric Class 10.9 hardware, with Certificates of Conformance and lot traceability records maintained on-site and available for review.

Your suspension system is not the place to compromise on quality.

About BDE-Systems LLC

Founded in 2014, Botello Dynamic Engineering (BDE) Systems LLC was established to bring innovative products and solutions to the Corvette community. Based in Ventura County, California, we proudly source our materials within the United States.

As a disabled U.S. Navy Veteran-owned business, we remain committed to quality, innovation, and customer service. A portion of our eBay sales supports the Navy SEAL Foundation and its mission to assist Naval Special Warfare families and veterans.

Thanks to the support of the Corvette community, we have expanded beyond the C4 platform into the C2, C3, C5, C6, and C7 markets while continuing to develop, test, and refine new products using our own Corvette fleet.

Eli Botello
Owner, BDE-Systems LLC