Qa1 Coilover Kit Review

How to choose qa1 coilover kit

Spring rate before anything else

QA1 sizes its front systems by front-end weight, not by guesswork. A 250 lb spring suits a light small-block front end, while a 750 lb spring suits a big-block car, and the wrong rate gives either a harsh ride or a car that bottoms out. Weigh the front end or use QA1’s published weight bands.

Single versus double adjustable

Single-adjustable shocks change rebound and compression together in 18 positions, while double-adjustable shocks give 18 compression and 18 rebound positions for 324 combinations. Double adjustability suits tuners; single adjustability suits drivers who want one knob and a good street setup.

Bolt-in versus fabrication

These Pro Coil systems are sold as bolt-in conversions with brackets and hardware, with no cutting or welding in the maker description. Confirm that claim against your exact year and model, because bracket shapes differ across GM platforms.

Ride height and stance

A fully threaded shock body lets you set ride height precisely, and QA1 front systems are rated for up to a 2-inch drop in the published specs. Set height with the car at full weight and aligned afterwards, not on jack stands.

Rebuildability and support

QA1 shocks are dyno tested and serialised, and rebuildable through QA1 or authorised centres. That matters on a car you plan to keep, because a serviceable shock outlasts a sealed throwaway unit.

Alignment after install

Any ride-height or suspension change needs a fresh alignment. Budget for it in the job, and recheck after the springs settle, or new handling gains will be eaten by tyre wear.

System position and fitment

More guides in this area: related guide, related guide, related guide, related guide.

Qa1 Coilover Kit Review by budget

Types of qa1 coilover kit

Before you buy any qa1 coilover kit option, write down the one job it must do well, the size or fitment limit it must meet, and the maintenance you will actually keep up. That short list prevents the most common regret in this category: buying the most featured option instead of the one that fits your vehicle, your space and your routine. The top pick in this guide, QA1 RCK52333 Pro Rear Double Adjustable Coil-Over Kit, is the best starting point for most readers, but the other picks exist because vehicles, budgets and uses differ.

Detailed reviews

Each review below follows the same structure: why it is a pick, key specifications, fits and best use, pros and watch-outs, what owners report, who should not buy it, and what to pair it with. Read the pick that matches your use first, then compare its specifications against the runner-up, because small differences in size, fitment or power decide whether a good product is good for you.

Best double-adjustable rear: QA1 RCK52333 Pro Rear Double Adjustable Coil-Over Kit

Best double-adjustable rear

Why the QA1 RCK52333 Pro Rear Double Adjustable Coil-Over Kit is our pick

The RCK52333 is a rear Pro Coil conversion kit with double-adjustable shocks, giving independent compression and rebound control for tuners who want to dial in the rear end separately from the front. Like other QA1 rear kits, it is sold with brackets, springs and hardware as a bolt-in conversion, with ride-height adjustment from the threaded shock body. Its Amazon listing makes it the easiest rear kit here to buy, and its double adjustability is the reason to choose it over a single-adjustable rear kit.

In daily use, the QA1 RCK52333 Pro Rear Double Adjustable Coil-Over Kit is best understood through two of its defining details: Brand: QA1 and Part number: RCK52333. Those details explain both its strengths above and its limits, so compare them against your own vehicle, space and routine before ordering, and confirm fitment or size against the maker listing.

QA1 RCK52333 Pro Rear Double Adjustable Coil-Over Kit key specs

• Brand: QA1
• Part number: RCK52333
• Type: Pro Rear Coil-Over Kit
• Adjustability: Double adjustable
• Position: Rear
• Install: Bolt-in conversion with brackets
• Ride height: Adjustable
• Shocks: QA1 adjustable aluminium shocks
• Springs: High-travel springs included
• Best for: Tuned rear suspension

QA1 RCK52333 Pro Rear Double Adjustable Coil-Over Kit: fits and best for

Best for GM rear conversions where the owner wants independent compression and rebound tuning, especially on street and strip cars.

QA1 RCK52333 Pro Rear Double Adjustable Coil-Over Kit pros and watch-outs

QA1 RCK52333 Pro Rear Double Adjustable Coil-Over Kit: what owners report

QA1 RCK52333 Pro Rear Double Adjustable Coil-Over Kit: who should not buy

If you want simple street tuning, a single-adjustable system is easier to live with than this double-adjustable kit.

QA1 RCK52333 Pro Rear Double Adjustable Coil-Over Kit: pair it with

Pair it with a matched front Pro Coil system so front and rear rates work together.

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Tip: start both adjustments in the middle, then change one at a time and note the effect. Related reading: See this related guide.

Best second rear option: QA1 RCK52337 Pro Rear Double Adjustable Coil-Over Kit

Best second rear option

Why the QA1 RCK52337 Pro Rear Double Adjustable Coil-Over Kit is our pick

The RCK52337 is the companion rear kit to the RCK52333, sharing the double-adjustable Pro Coil formula: independent compression and rebound adjustment, bolt-in brackets, high-travel springs and adjustable ride height. The two kits differ by application, so the choice between them is a fitment question, not a quality ranking. Check the QA1 application data for your exact year and model, and do not assume one rear kit fits all GM rear ends.

In daily use, the QA1 RCK52337 Pro Rear Double Adjustable Coil-Over Kit is best understood through two of its defining details: Brand: QA1 and Part number: RCK52337. Those details explain both its strengths above and its limits, so compare them against your own vehicle, space and routine before ordering, and confirm fitment or size against the maker listing.

QA1 RCK52337 Pro Rear Double Adjustable Coil-Over Kit key specs

• Brand: QA1
• Part number: RCK52337
• Type: Pro Rear Coil-Over Kit
• Adjustability: Double adjustable
• Position: Rear
• Install: Bolt-in conversion with brackets
• Ride height: Adjustable
• Shocks: QA1 adjustable aluminium shocks
• Springs: High-travel springs included
• Best for: Application-specific rear fitment

QA1 RCK52337 Pro Rear Double Adjustable Coil-Over Kit: fits and best for

Best for GM rear conversions where the RCK52333 application does not fit, with the same double-adjustable tuning.

QA1 RCK52337 Pro Rear Double Adjustable Coil-Over Kit pros and watch-outs

QA1 RCK52337 Pro Rear Double Adjustable Coil-Over Kit: what owners report

QA1 RCK52337 Pro Rear Double Adjustable Coil-Over Kit: who should not buy

If the RCK52333 fits your car, there is no handling reason to prefer this kit over it.

QA1 RCK52337 Pro Rear Double Adjustable Coil-Over Kit: pair it with

Pair it with a front system matched to your front-end weight, not to this rear kit alone.

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Tip: confirm the application by part number against QA1 data before ordering either rear kit. Related reading: See this related guide.

Best small-block front: QA1 GS401-10400A Pro Coil Front System

Best small-block front

Why the QA1 GS401-10400A Pro Coil Front System is our pick

The GS401-10400A is a front Pro Coil system for small-block F and X-body cars, with single-adjustable shocks, a fully threaded body and a 400 lb spring rate suited to front ends of 1,801 to 1,900 lb. It is sold in pairs with springs and hardware, and QA1 describes it as a bolt-in system with ride-height adjustment. Because no verified Amazon listing was found for this part number, buy it through a specialist retailer and use the Amazon alternative below for the affiliate option.

In daily use, the QA1 GS401-10400A Pro Coil Front System is best understood through two of its defining details: Brand: QA1 and Part number: GS401-10400A. Those details explain both its strengths above and its limits, so compare them against your own vehicle, space and routine before ordering, and confirm fitment or size against the maker listing.

QA1 GS401-10400A Pro Coil Front System key specs

• Brand: QA1
• Part number: GS401-10400A
• Type: Pro Coil Front System
• Adjustability: Single adjustable
• Position: Front
• Spring rate: 400 lb per inch
• Front-end weight band: 1,801 to 1,900 lb
• Install: Bolt-in, sold in pairs
• Ride height: Adjustable via threaded body
• Best for: Small-block F and X-body

QA1 GS401-10400A Pro Coil Front System: fits and best for

Best for 1967-1974 Camaro, Nova and related F and X-body cars with small-block front ends.

QA1 GS401-10400A Pro Coil Front System pros and watch-outs

QA1 GS401-10400A Pro Coil Front System: what owners report

QA1 GS401-10400A Pro Coil Front System: who should not buy

If your front end is outside the 1,801 to 1,900 lb band, choose a different spring rate rather than forcing this one.

QA1 GS401-10400A Pro Coil Front System: pair it with

Pair it with a rear QA1 kit so the car is balanced front to rear.

Sold through specialist retailers: See the retailer listing.

Alternative with an affiliate link: if the specialist-retailer option above is unavailable, the verified Amazon alternative below carries its own affiliate link.

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Tip: weigh the front end with a full tank and normal equipment before ordering. Related reading: See this related guide.

Best A-body front: QA1 GS401-11250C Pro Coil Front System

Best A-body front

Why the QA1 GS401-11250C Pro Coil Front System is our pick

The GS401-11250C is a front Pro Coil system with a 250 lb spring, 18-position single adjustment, twin-tube aluminium shocks and a threaded body giving up to a 2-inch drop. Summit lists its recommended front-end weight at 1,500 to 1,600 lb, with an extended length of 12.88 inches and a collapsed length of 8.63 inches. It suits lighter small-block A, G and X-body cars, and it is the most forgiving front system here for street use.

In daily use, the QA1 GS401-11250C Pro Coil Front System is best understood through two of its defining details: Brand: QA1 and Part number: GS401-11250C. Those details explain both its strengths above and its limits, so compare them against your own vehicle, space and routine before ordering, and confirm fitment or size against the maker listing.

QA1 GS401-11250C Pro Coil Front System key specs

• Brand: QA1
• Part number: GS401-11250C
• Type: Pro Coil Front System
• Adjustability: Single adjustable, 18 positions
• Position: Front
• Spring rate: 250 lb per inch
• Front-end weight band: 1,500 to 1,600 lb
• Shock design: Twin-tube, aluminium body
• Extended length: 12.88 in
• Collapsed length: 8.63 in
• Height adjustment: Up to 2 in drop
• Install: Bolt-in, sold in pairs

QA1 GS401-11250C Pro Coil Front System: fits and best for

Best for 1973-1988 GM A, G and X-body cars with light small-block front ends around 1,500 to 1,600 lb.

QA1 GS401-11250C Pro Coil Front System pros and watch-outs

QA1 GS401-11250C Pro Coil Front System: what owners report

QA1 GS401-11250C Pro Coil Front System: who should not buy

If your front end is over 1,600 lb, step up a spring rate instead of running this system soft.

QA1 GS401-11250C Pro Coil Front System: pair it with

Pair it with a rear kit and a fresh alignment for a balanced street setup.

Sold through specialist retailers: See the retailer listing.

Alternative with an affiliate link: if the specialist-retailer option above is unavailable, the verified Amazon alternative below carries its own affiliate link.

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Tip: set height with the car at full weight, then align before judging ride quality. Related reading: See this related guide.

Best big-block front: QA1 GS401-10750C Pro Coil Front System

Best big-block front

Why the QA1 GS401-10750C Pro Coil Front System is our pick

The GS401-10750C is the heavy front-end answer in this guide: a single-adjustable Pro Coil system with a 750 lb spring, twin-tube aluminium shocks and the same threaded-body height control, listed by Summit for front ends of 2,401 to 2,600 lb. Big-block cars punish an undersprung front end with bottoming and poor control, so this rate is not overkill for its band; it is the correct match. Confirm the band with a real front-end weight before ordering.

In daily use, the QA1 GS401-10750C Pro Coil Front System is best understood through two of its defining details: Brand: QA1 and Part number: GS401-10750C. Those details explain both its strengths above and its limits, so compare them against your own vehicle, space and routine before ordering, and confirm fitment or size against the maker listing.

QA1 GS401-10750C Pro Coil Front System key specs

• Brand: QA1
• Part number: GS401-10750C
• Type: Pro Coil Front System
• Adjustability: Single adjustable, 18 positions
• Position: Front
• Spring rate: 750 lb per inch
• Front-end weight band: 2,401 to 2,600 lb
• Shock design: Twin-tube, aluminium body
• Extended length: 12.88 in
• Collapsed length: 8.63 in
• Height adjustment: Up to 2 in drop
• Install: Bolt-in, sold in pairs

QA1 GS401-10750C Pro Coil Front System: fits and best for

Best for GM big-block front applications in the 2,401 to 2,600 lb front-end band.

QA1 GS401-10750C Pro Coil Front System pros and watch-outs

QA1 GS401-10750C Pro Coil Front System: what owners report

QA1 GS401-10750C Pro Coil Front System: who should not buy

If your front end is under 2,400 lb, this spring will ride harshly; choose a lower rate.

QA1 GS401-10750C Pro Coil Front System: pair it with

Pair it with a rear system rated for the car’s total weight and intended use.

Sold through specialist retailers: See the retailer listing.

Alternative with an affiliate link: if the specialist-retailer option above is unavailable, the verified Amazon alternative below carries its own affiliate link.

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Tip: big-block weight includes accessories and cooling, so weigh the car as driven, not as listed. Related reading: See this related guide.

Spec comparison

The tables below line up the same specifications side by side so differences stand out. Where a figure is marked Not published, the maker or listing did not state it during research, and this guide does not guess it. Use the tables to shortlist two options, then read their full reviews before deciding.

Installation & wiring basics

Install coil-overs with the car supported properly and the suspension at a safe working height, never relying on a jack alone. Fit brackets and hardware per the QA1 instructions for your exact kit, torque fasteners to spec, and set ride height with the car on the ground at full weight. Adjust valving to the middle of its range first, drive gently, then tune one end at a time so you know what changed. Book an alignment immediately after install, and recheck ride height and fasteners after the first miles, because new springs settle and hardware can shift.

After fitting, recheck everything after the first short use: fasteners settle, straps stretch, hoses seat and mirrors shift. A five-minute recheck catches most early problems before they become failures, and it is worth doing even when the first fit felt perfect. Keep the maker instructions with the vehicle documents, because the next owner or the next service will need the same fitment and specification details.

Helpful internal guides: related guide, related guide, related guide.

Safety essentials

Safety in this category is mostly about preparation rather than heroics: correct fitment, honest limits and a recheck after the first use. The six rules below cover the failures that cause most avoidable damage, and they apply to every pick in this guide regardless of budget or brand.

Accessory safety reading: See this safety-related guide.

Safety accessory: QA1 RCK52333 Pro Rear Double Adjustable Coil-Over Kit.

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Safety accessory: QA1 RCK52337 Pro Rear Double Adjustable Coil-Over Kit.

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Safety accessory: QA1 GS401-10400A Pro Coil Front System.

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Troubleshooting

Work through this table from the symptom you actually have, not from the fix you hope for. Most faults in this category trace to fitment, wear or a missed maintenance step, and the cheapest fix is usually the correct diagnosis made early, before a small fault damages neighbouring parts.

Who should NOT buy these

If you have not weighed the front end, do not order by engine size alone. Two small-block cars can sit in different QA1 weight bands, and the wrong spring rate ruins the whole job. Weigh it or use the published bands honestly.

If you want a fit-and-forget setup, double-adjustable shocks may frustrate you. Single-adjustable systems give a good street result with one knob, while double adjustability rewards drivers who enjoy tuning.

If your car is a daily driver on rough roads, a very low stance plus firm valving will punish you. Keep usable ride height and a street-friendly valving setting rather than chasing a show stance.

If the budget only covers one axle, do that axle properly rather than buying cheap front and rear parts together. A matched single-axle QA1 system beats a mismatched full set.

Final verdict

If you want one line per pick, this is it. Start with the top pick for most uses, then move down the list only when a specific fitment, size or budget reason pushes you to a different option. Every pick below links to its own buying option, so the verdict is a shortcut, not a substitute for the reviews above.

Best double-adjustable rear – QA1 RCK52333 Pro Rear Double Adjustable Coil-Over Kit

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Best second rear option – QA1 RCK52337 Pro Rear Double Adjustable Coil-Over Kit

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Best small-block front – QA1 GS401-10400A Pro Coil Front System: Check its price (retailer listing; Amazon alternative in its review above).

Best A-body front – QA1 GS401-11250C Pro Coil Front System: Check its price (retailer listing; Amazon alternative in its review above).

Best big-block front – QA1 GS401-10750C Pro Coil Front System: Check its price (retailer listing; Amazon alternative in its review above).

FAQ

What is a QA1 Pro Coil kit?

A Pro Coil kit replaces factory shocks and springs with a threaded coil-over shock and a high-travel spring, giving adjustable ride height and valving. Front systems are sold in pairs with springs and hardware, and rear systems are bolt-in conversion kits with brackets.

How do I choose a QA1 spring rate?

QA1 publishes front-end weight bands for each spring rate. A 250 lb spring suits roughly 1,500 to 1,600 lb front ends, a 400 lb spring suits 1,801 to 1,900 lb, and a 750 lb spring suits 2,401 to 2,600 lb. Weigh your front end or confirm with QA1 tech support.

What is the difference between single and double adjustable QA1 shocks?

Single-adjustable shocks change rebound and compression together across 18 positions. Double-adjustable shocks give 18 compression and 18 rebound positions independently, for 324 combinations, which suits tuners who adjust each end separately.

Are QA1 coilover kits bolt-in?

The maker describes Pro Coil systems as easy bolt-in installations with no cutting or welding, including brackets and hardware. Always confirm against your exact year, model and engine, because bracket shapes vary across GM platforms.

Do QA1 shocks need rebuilding?

QA1 shocks are dyno tested, serialised and rebuildable through QA1 or authorised service centres. That serviceability is a long-term advantage over sealed shocks, especially on cars kept for years.

Will a QA1 kit lower my car?

Front Pro Coil systems in this guide are rated for up to a 2-inch drop via the threaded body adjustment. Set the height at full weight, then align the car, because lowering changes camber and toe.

Can I buy QA1 kits on Amazon?

Some rear conversion kits, including the RCK52333 and RCK52337, have Amazon listings. Front Pro Coil systems in this guide are sold through specialist retailers such as Summit Racing and Speedway Motors, with an Amazon alternative noted under each.

Do I need an alignment after fitting coil-overs?

Yes, always. Any ride-height or suspension geometry change alters alignment settings, and driving without one wears tyres and dulls handling. Recheck after springs settle.

How long should qa1 coilover kit last?

Life depends on use, climate and maintenance more than on brand alone. In this category, the products that last longest are usually the ones fitted correctly, kept clean and inspected regularly, while the ones that fail early are usually the ones fitted to the wrong application or left unmaintained. Check wear points at every service and replace a worn part before it damages neighbouring components.

What should I check before ordering qa1 coilover kit?

Check fitment first, then size, then the specification that matters most for your use, and finally the maintenance the product will need. Measure rather than guessing, compare the old part or the existing setup side by side where possible, and confirm the part number or model against the maker listing before ordering, because returns cost time even when they cost nothing else.

Sources

• Amazon listing: QA1 RCK52333 (ASIN B00GKGXWM6)
• Amazon listing: QA1 RCK52337 (ASIN B00GKGY4MI)
• Summit Racing QA1 GS401-11250C listing
• Summit Racing QA1 GS401-10750C listing
• Speedway Motors QA1 GS401-11250C listing

Sources above are the maker, retailer and listing pages used during research, plus the roundups and owner discussions cited in individual reviews. Where a listing and a maker page disagreed, this guide printed the disagreement rather than choosing silently, and where a figure was unpublished, it is marked as such.

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