Corvette C2 & C3 1963-1982, Adjustable Suspension System - Lowering 9" Bolt Drop Kit w/BLACK Poly Bushings + Spring Cups (14pc Set)

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Energy Suspension Bushings & Volunteer Vette Cups:
C2 & C3 Lowering Kit

Botello Dynamic Engineering (BDE) Systems LLC - Chevrolet Corvette C2 & C3, Suspension Lowering 9" Bolt Kit for 1963-1982 Corvettes (BLACK BUSHINGS), Complete 14-piece rear kit.

What's included with this sale:

  • QTY (2) Grade 8 Bolts, DIN 931 Metric in a 9" length in Yellow Zinc Chromate Plating - Our custom manufactured length for this C2/C3 Corvette application – Made in the USA.
  • QTY (4) Grade 8 1.73” OD Oversized Washers, in Yellow Zinc Chromate Finish – Correctly oversized washers – Made in the USA.
  • QTY (2) Grade 8 Steel Nyloc (Locking) Nuts with Flared Base, in Yellow Zinc Chromate Finish – Made in the USA.
  • QTY (2) Volunteer Vette Products, Rear Spring Mount Cups – Made in the USA (Tennessee).
  • QTY (4) Energy Suspension Rear Bushings (1 complete rear set) made of Energy's HYPERFLEX Performance Polyurethane – Made in the USA – Style/Color: LOW-PROFILE, BLACK BUSHINGS
  • QTY (1) Install Instructions – Basic pamphlet guide including color images.
  • QTY (1) Packing Slip
  • QTY (1) USPS Priority Mail Shipping (2-3 Day Service) with tracking & insurance; USA customers only

***International Customers Pay $19.99USD for Export/Import, VAT Fees, International Customs Paperwork, Tracking and Delivery***


If you are reading this, then chances are you don't necessarily like the wheel gap presently in your C2 or C3 Corvette. BDE-Systems has experience in lowering kits for Corvettes and due to the success of our long and best-selling C4 & C5 lowering kits and brake upgrade kits, we now offer a kit for C2 & C3 Corvettes. We worked with our shops Alex Retana's 1969 RestoMod C3 Corvette, along with a couple of users from the CorvetteForum Community in this development. Short going to a custom coil-over/track setup, our C2 & C3 Corvette Lowering Kits will improve the look and ride of your Corvette in short order, while saving your hard-earned money.

THIS LOWERING/RIDE HEIGHT PROVIDED BY THIS KIT IS ADJUSTABLE TO YOUR LIKING as it includes a lengthy threaded rod for which you to make your adjustments as needed. We tried 10" bolts but, in our experience, they may be too long for some customers, causing potential wheel/tire interference or damage on certain models. Although we are experienced in longer and shorter lowering bolt kit Corvette applications, we ultimately settled on our 9" cut bolts for the C2/C3 market. If you desire a shorter or longer bolt, we can swap it in for you, simply email us as we always stock materials here in our Ventura County office or via our LLC FBA warehouse.  

As mentioned, this C2/C3 kit was developed using Alex Retana's RestoMod 1969 C3 along with a few members from The CorvetteForum and their vehicles. We took valuable input on a variety of suspension needs and formulated the kit presented here today. In addition, we test and run all our kits and products on our very own BDE-Systems Corvettes that we are lucky to own:

  1. 1987 Corvette TPI - Modded
  2. 1994 Corvette LT1 - Modded
  3. 2003 Corvette Z06 - Modded
  4. C6 Z06 we presently have at 714 crank HP on E85, our 2020 addition to the stable.

Rest assured; we aren't a reseller or parts flipper looking for a cheap & quick dollar - We daily drive what we sell, CORVETTE.



Strength Matters

BDE-Systems Lowering Bolts have been meticulously engineered to adhere to the highest standards of quality and strength. Our bolts are classified as Grade 8/Metric Class 10.9, complying with the esteemed DIN 931 certification. Furthermore, it is essential to highlight that the entire hardware kit provided by BDE-Systems LLC also meets or surpasses the rigorous Grade 8 standards as outlined by ASTM A324 Grade BD and SAE J429. This guarantees the utmost level of quality, durability, and strength in the components.

It is important to emphasize the significance of these designations, as it is not uncommon to find kits in the market that utilize Grade 5 hardware instead. Such a substitution of the original Grade 8 design not only bypasses the scrutiny of GM's Engineering Team but also poses a risk to both your vehicle and personal safety. These shortcuts are typically motivated by cost-saving measures, compromising the integrity and performance of the kit.

Grade 5 hardware is characterized by its lower quality and is primarily intended for general applications, such as carpentry, household use, and low-stress domestic purposes. The absence of appropriate certificates of conformance or lot traceability for lower tensile strength hardware further emphasizes the disparity in quality. Conversely, Grade 8 hardware, like that employed by BDE-Systems, undergoes stringent testing, and conforms to specific standards, ensuring its suitability for demanding automotive applications. Grade 8 hardware stands as a superior choice compared to Grade 5 due to several significant factors that contribute to its enhanced strength and reliability. In the realm of fasteners and mechanical components, the grading system provides a standardized means of categorizing the tensile strength and overall quality of materials used. Here are the key reasons why Grade 8 hardware surpasses Grade 5:

  • Tensile Strength: Grade 8 hardware exhibits a higher tensile strength compared to Grade 5. Tensile strength refers to the maximum load a fastener can bear before breaking. Grade 8 fasteners are engineered to withstand greater forces and loads, making them ideal for applications that demand high load-bearing capacities and structural integrity.
  • Carbon Content: The disparity in tensile strength can be attributed to the higher carbon content in Grade 8 hardware. Carbon is a crucial element that enhances the strength and hardness of the material, enabling Grade 8 fasteners to withstand greater stress and deformation without compromising their integrity.
  • Alloying Elements: In addition to carbon, Grade 8 hardware incorporates alloying elements such as chromium, molybdenum, and vanadium, among others. These elements further enhance the strength, hardness, and overall performance of the fasteners, providing them with superior resistance against deformation, shearing, and fatigue.
  • Durability: The increased strength and robustness of Grade 8 hardware translates into improved durability. Grade 8 fasteners are designed to withstand harsh conditions, heavy vibrations, and extreme temperatures without compromising their structural integrity. This durability ensures long-term reliability and minimizes the risk of failure or damage.
  • Safety and Reliability: The use of Grade 8 hardware ensures a higher level of safety and reliability in critical applications. By utilizing fasteners with superior strength and load-bearing capabilities, the risk of fastener failure, structural collapse, or mechanical breakdown is significantly reduced, enhancing overall operational safety and stability.
  • Industry Standards: Grade 8 hardware adheres to strict industry standards and specifications, such as those outlined by organizations like the American Society for Testing and Materials (ASTM) and the Society of Automotive Engineers (SAE). These standards ensure consistent quality and performance, as well as compatibility with various industry applications and requirements.

In summary, Grade 8 hardware surpasses Grade 5 in terms of tensile strength, carbon content, alloying elements, durability, safety, and compliance with industry standards. The superior properties of Grade 8 fasteners make them the preferred choice for applications that demand robustness, reliability, and optimal performance under demanding conditions. By selecting Grade 8 hardware, engineers, manufacturers, and individuals can ensure the longevity, safety, and efficiency of their projects or equipment.

  • Common Aftermarket Bolt Rating: Grade 5 or worse - It is important to note that a common rating for aftermarket bolts is often Grade 5 or even lower. When purchasing from a vendor who does not explicitly specify the Grade/Class Bolt, there is a high probability that substandard materials are being used. These inferior materials are typically obtained at lower costs locally or through online channels, and then resold to unsuspecting customers.
  • BDE-Systems Bolt Rating: Grade 8/Class 10 - Our bolt grade matches the OEM GM factory bolt Grade 8 rating.

Grade 8 bolts exhibit superior tensile and shear strength compared to Grade 5 bolts, with certified levels of over 21% higher in shear strength and 25% higher in fatigue/tensile failure levels. This advantage extends to metric bolts as well, specifically when comparing Class 8.8 to Class 10.9. The lower grade bolt, in both cases, reaches its maximum elongation and fracture point significantly earlier than the higher-grade bolt, which demonstrates its superior resistance to deformation.

Since the 1950s, General Motors (GM) has been utilizing Class 10/Grade 8 bolts in the rear suspension of their automobiles and Corvettes. The selection of Class 10/Grade 8 bolts by GM reflects their confidence in the strength and reliability of these bolts for critical automotive applications. It is worth noting that all BDE-SYSTEMS LLC kits we offer maintain the same class/grade as the original equipment manufacturer (OEM) used by GM plants. By aligning with GM's choice of Class 10/Grade 8 bolts, BDE-SYSTEMS LLC ensures that their kits maintain the highest standards of quality and performance. This commitment to utilizing the same class/grade as the OEM highlights their dedication to delivering products that meet or exceed the specifications and requirements set by reputable automotive manufacturers. 

Here is just a small sample size of CorvetteForum users that you can look up as they have had their lower GRADE 5 BOLTS FAIL - You don't need to purchase from us but please ENSURE you are getting GRADE 8 materials only: 

  • CorvetteForum Senior Member Greengear - failed lower grade bolts
  • CorvetteForum Senior Member Kinkajou - failed lower grade bolts
  • CorvetteForum Senior Member FR 73 454 - failed lower grade bolts
  • CorvetteForum Senior Member Danbo - failed lower grade bolts
  • CorvetteForum Senior Member C5Natie , he and I had our friend in LA total his C4 over a weaker rear bolt failing at highway speeds, fortunately accident was not fatal - failed lower grade bolts




 Quality and Certification Matters

BDE-Systems LLC is an approved Amazon FBA Business Partner (2023). We maintain on-site Certificates of Conformance and Lot Traceability records for the materials utilized in our products. While we have done this for many years, our recent certification meant that our records underwent a thorough evaluation by LLC during the application process for our current Amazon FBA Business Account, resulting in successful approval. By diligently preserving Certificates of Conformance (CoC) and Lot Traceability records, we uphold a high standard of accountability and quality assurance. These records serve as tangible evidence of our commitment to meeting and exceeding industry requirements and regulations, and our commitment to you. The evaluation and approval of our records by LLC for our Amazon FBA Business Account further validates our adherence to stringent quality control measures. This endorsement from a reputable platform highlights our dedication to upholding the highest standards in our business operations.

When evaluating kits or components, it is crucial to prioritize transparency regarding the material, grade, and class of the hardware being utilized. Kits that fail to mention or provide details about the hardware used are highly likely to incorporate Grade 5 alternatives. By being vigilant and selecting kits that adhere to Grade 8 standards, you can safeguard the performance, reliability, and safety of your vehicle.

Our hardware finish exceeds OEM GM standards as our bolts, nuts and washers are treated to a yellow zinc chromate coating to protect your new kit from the natural elements for many years to come. Yellow zinc chromate is a chemical conversion coating that is applied over zinc plating during the surface coating process. Zinc plating is a soft, ductile, marginally solderable, corrosion-resistant finish. It protects the substrate and corrodes before the base metal, unlike most other commonly plated metals, thus protecting your new Grade 8 Steel parts.

With the combination of the rear Grade 8/Class 10.9 bolts, Volunteer Vette Products Spring Cups, Grade 8 non-marring flanged nyloc nuts, Grade 8 oversized washers (hardware in a matching yellow zinc chromate, providing years of protection from the elements) and Hyperflex Polyurethane bushings, this is the best quality and performance C2 & C3 bolt lowering kit that any Corvette manufacturer or vendor carries.




Adjustability Matters

Our hardware finish BDE-Systems C2 & C3 Lowering Bolts provide an increase of 2.80" in overall length when compared to the OEM bolts, this allows for an extended threaded rod portion to be used for compressing/decompressing of the C2/C3 suspension, which provides a substantial range of ride height adjustment. We found that the 8" bolt length would leave some adjustment room on the table and often left the nut at the end of the bolt threads. We tried a 10" bolt and while it worked, it’s not a length we recommend on certain models as select aftermarket wheels may change the wheel offset/height/width and in turn, alter the general suspension geometry and spacing in relation to the bolts/suspension components vs the wheel/tire, possibly causing interference or a tire puncture. We found the 9" bolt to be an excellent compromise in both areas, lowering/adjustable range and maintained a safe distance from potential interference with the rim and tire, even with aftermarket wheels. IF YOU DESIRE A SHORTER OR LONGER BOLT KIT, WE STOCK IT AND CAN SWAP IT IN – EMAIL US FOR YOUR NEEDED KIT LENGTH AT NO ADDITIONAL COST.




 Trusted Partnerships Matter - Completing the Package:


  1. When replacing the rear spring bolts, we decided to include a pair of C2-C3 Rear Spring Cushion Retainers to replace the old worn hardware in your Corvette - Doing it once, means doing it right.
  2. These C2 & C3 Rear Spring Cushion Retainers have been sold to hundreds of Volunteer Vette Customers and are a GUARANTEED fit in the replacement/restoration of your OEM retainers.
  3. These are manufactured specifically by Volunteer Vette Products for our BDE-Systems Suspension C2 & C3 Lowering Kits.

To round off our Complete Rear Lowering Kit, we've partnered with Energy Suspension Bushings for our bushing needs. Energy Suspension is a well-established company in the suspension market for OEM or aftermarket components with an impeccable reputation in the field. 

Have you ever heard the rear of your Corvette squeak and squeal? Or perhaps notice a slight height difference between each side? It could be that your original crushed rubber pads have gone out on you. When replacing the rear bolts, out along will come the OEM GM rubber pads that will most likely be beat down and cracked so why not take this moment to replace them with Energy Suspension’s Hyperflex Performance Polyurethane? Longer lasting performance polyurethane pads are smart to install whenever the spring assembly is reassembled. Benefits of our low-profile poly pads:

  1. Adds a dramatic amount of performance and durability to any vehicle
  2. Helps the vehicle be in control when maneuvering through turns, during standing start accelerations, braking, even over bumps and berms.
  3. Made of Energy's HYPERFLEX performance polyurethane.
  4. Improved traction and handling


The Advantages of Lowered/Adjustable Suspension

In general, having the vehicle lower to the ground can increase the grip of the tires on the roadway by reducing the suspension travel to have body weight and momentum shifted to the rear wheels. Additional stiffness can be desired in a suspension, and this is one of the perks that some drivers mention after lowering their suspension.

Body roll reduced
When the center of gravity has lowered one generally reduces body roll which in turn increases the responsiveness of the car. C4 Corvettes aren't known rollover adverse vehicles but if there was a threshold or propensity of it, it would be reduced by lowering it.
Stock wheels and body spacing
This may not be news to you C2 and C3 Corvette owners out there, but the suspension and ride height varies from Corvette to Corvette. Reports vary on stock height, but we've seen heights from about 26" to about 30", and we attribute this to suspension condition, year & model variances in suspension options and miles on suspension. This kit is an excellent way to remedy those variances and stabilize the rear end.
Aftermarket wheels and body spacing
When moving into the aftermarket wheel world it is often a necessity to lower the ride height of one’s vehicle to close the wheel gap and achieve that perfect stance. Our 1994 Corvette has 19" aftermarket wheels while our 1987 Corvette has 17" aftermarket wheels (OEM wheels were 16") so the kits allowed us to match the wheels to the ride height very easily – This will apply to your C2 and C3, the adjustability will work with your wheel and tire setup.
Better aerodynamics
With a lowered suspension, there's less air going underneath the vehicle, and this can create a better outcome for wind drag on a car. GM did design the vehicle with a rake for stability at high speed so keep at rake if that's your intended range - adjusting and monitoring the height at speed in conjunction with adjustments is recommended. The speeds we are talking about are off-road speeds not seen on commercial/commuter/highway roads. In other words, adjusting your height is fine for regular street and highway use without need to worry but if you drive in the 130+MPH range for sustained periods of time then monitoring/adjustments are recommended, just like any other lowering.



  1. Buy from anyone you'd like but for your own safety, find a reputable manufacturer, reseller or source as a few dollars difference CAN buy peace of mind.
  2. DONT REPLACE YOUR OEM Bolts WITH GRADE 5, CLASS 8, unmarked, OR local hardware surplus parts.
General and/or Limited Liability clauses WILL NOT protect a corporation, company, or individual selling lower grade hardware in place of the OEM Grade 8 hardware.
Please bear in mind that ultimate shear strength of a fastener is typically about 60% of its ultimate tension strength. In addition, cyclic fatigue and continual loading cycles will EVENTUALLY stress the subpar steel leading to a failure (usually at speed, under road strain).
GM and nearly all vehicle manufacturers use GRADE 8 Bolts in high stress suspension components such as the rear of your Corvette.
BDE-Systems LLC will only sell you the correct, OEM strength Metric Class 10.9/Grade 8 Hardware Required by General Motors Corp. Certs of Conformance and Lot Traceability records kept on site and are available for review.




FREE USPS Priority Shipping & Tracking is included to The United States with the sale price unless otherwise noted.

***WORLDWIDE SHIPPING! *** We can ship to virtually any address in the world and are glad to serve our Corvette Customers overseas. The free shipping applies only to Continental US customers, but we do have a global business shipping account and all other locations only pay a flat rate of $19.99 as the International Shipping Rate. This includes customs paperwork, export/import and VAT fees.

Items will be shipped within 1 business day after receiving a clear payment, same day shipping is carried out when/where possible.


 Returns Policy

We accept returns although we rarely see them; however, if there is ever an issue or concern, we are always willing to work it out if you contact us immediately. We will always strive to reach an amicable agreement upon any reports of concerns. You may also return an item if we shipped the incorrect item to you (wrong color or incorrect item) - at which point we will refund the new, unused item cost within 14 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received the wrong color or incorrect item, etc.). You should expect to receive your refund within three weeks of giving your package to the return shipper, however, in many cases you will receive a refund within a faster time frame, that is a worst case/special circumstance scenario. This period includes the transit time for us to receive your return from the shipper (3 to 7 business days), the time it takes us to process your return once we receive it (2 to 4 business days), and the time it takes the bank system to process our refund request (1 to 2 business days). We strive to ensure your satisfaction and our customer support line is there to walk you through the installation, answer technical questions and offer advice on installation methods. If you need to return an item, please Contact Us with your order number and details about the product you would like to return. We will respond quickly with instructions for how to return items from your order.


Thank you for taking the time to visit us here at Botello Dynamic Engineering (BDE) Systems LLC. We were founded in 2014 with the intention of bringing the Corvette market a breath of fresh air with new products. We’re an LLC based out of Ventura County California and all our materials for our products are sourced in the United States. BDE-Systems is a minority owned, disabled US NAVY Veteran with all our eBay sales generating a percentage of charitable contributions to The NAVY SEALS FUND at Thanks to the response in the C4 Corvette market over the last few years, we have been able to expand into the C2, C3, C5, C6 and C7 market Corvette market - Due to all the continued and consistent sales/community support, we purchased a C5 Z06 and a C6 Z06 Corvette. These vehicles are not just enjoyed by us daily, they have served as "test mules" and allowed us to release/research additional products or services in this field; thankfully, we also gained new partnerships in the Corvette and Automotive Industry in doing so.


Thank you,

Eli Botello

Owner of BDE-Systems LLC

Energy Suspension Bushings & Volunteer Vette Cups:
C2 & C3 Lowering Kit
  • 5

    Posted by ron conklin on Apr 24th 2024

    awesome guys, easy job, vette looks good too,i think even faster,hahaa

  • 5
    Drop Bolts

    Posted by Bryce Rassilyer on Apr 20th 2024

    Drop bolts fit perfectly on my 69 vette. 9 inch bolts are significantly better than 10 inch I’ve seen. They don’t get in the way way other suspension components or the tires (I run 255/60-18’s.

  • 5
    Lowering Bolt Kit

    Posted by Rich Stavridis on Mar 18th 2024

    Excellent product Well made easy install. Would definitely recommend .

  • 5

    Posted by Nick on Jul 17th 2023

    Packed nice, shipped fast, had everything you need, and dropped my vette low! Very happy!