The LS platform has become legendary in the performance world, and for good reason. These engines respond incredibly well to modifications, parts are abundant and affordable, and with the right combination of components, achieving 700 horsepower at the wheels while maintaining daily-driver reliability is absolutely achievable. I've built dozens of 700+ horsepower LS engines here at Raw Exotics, and I'm going to share exactly how we do it.
The key word here is "reliable." Anyone can throw parts at an LS and make big power for a few dyno pulls. Building an engine that makes 700 wheel horsepower and lasts for years of street and strip use requires careful parts selection, meticulous assembly, and proper tuning. This guide covers everything you need to know.
Understanding the 700HP Target
Before we dive into parts, let's clarify what we're building. When I say 700 horsepower, I'm talking about wheel horsepower measured on a Dynojet chassis dyno, not inflated crank numbers. Depending on drivetrain losses, you're looking at roughly 800-850 horsepower at the crank. This is serious power that requires careful planning and quality components throughout the entire build.
At this power level, you're in the sweet spot where you can still run pump gas with the right combination of parts and tuning, maintain reasonable street manners, and enjoy excellent reliability if everything is done correctly. Push much beyond 700 wheel horsepower and you start needing race fuel, more aggressive components, and compromises in drivability.
Foundation: Choosing Your Block
The foundation of any reliable high-horsepower LS build starts with the right block. For 700 wheel horsepower, you have several excellent options, each with pros and cons.
LS3/L92/L9H/LY6 (6.2L)
These aluminum 6.2L blocks are my go-to recommendation for most 700hp builds. They come with a 4.065-inch bore, excellent cylinder head flow, and strong bottom ends that handle forced induction well. The LS3 is the most common, found in 2008+ Corvettes and Camaros. The L92/L9H/LY6 are truck variants with essentially the same block but different accessories.
These blocks can handle 700 wheel horsepower on the stock bottom end with proper tuning, though I always recommend at least upgrading to ARP head studs and a good tune. For maximum reliability at this power level, consider upgrading to forged pistons and better rods.
LSA/LS9 (Supercharged Variants)
If you're starting with an LSA from a CTS-V or ZL1, or the rare LS9 from a ZR1, you already have a fantastic foundation. These engines came factory-rated at 550-638 horsepower and were built to handle boost from the factory. The blocks are essentially LS3 variants but with forged internals, upgraded oiling, and stronger castings. Getting to 700 wheel horsepower is relatively straightforward with pulley upgrades, better flowing heads or porting, camshaft upgrades, and proper tuning.
Iron Block Options (LQ4/LQ9/L33)
Don't overlook iron blocks. The LQ4 (6.0L) and LQ9 (6.0L higher compression) from GM trucks are incredibly strong and affordable. Yes, they add about 100 pounds compared to aluminum, but they're virtually indestructible and handle nitrous and boost exceptionally well. For dedicated drag cars or builds where weight isn't critical, these are fantastic choices. Many 1,000+ horsepower street cars run iron blocks for their superior strength and crack resistance.
Building the Bottom End
Pistons
For reliable 700 wheel horsepower, especially with forced induction, forged pistons are mandatory in my book. Cast pistons might survive, but why risk a $10,000+ build to save $800 on pistons?
I typically spec Wiseco, JE, or CP pistons depending on the specific application. For boosted applications, you want a lower compression ratio—typically 9.0:1 to 9.5:1—to safely run pump gas. For naturally aspirated builds chasing 700 wheel horsepower (which requires displacement and RPM), you can run 11.5:1 to 12.0:1 compression but will need race fuel and aggressive tuning.
Ring gap is critical. For boosted applications at this power level, I typically gap top rings at 0.024-0.026 inches and second rings at 0.018-0.020 inches. Too tight and the rings will butt when they heat up, scoring the cylinder walls. Too loose and you'll have excessive blowby and oil consumption.
Connecting Rods
Stock LS rods are surprisingly stout, but at 700 wheel horsepower, you're at their limit, especially with the shock loads from forced induction. I recommend upgrading to H-beam or I-beam forged rods from manufacturers like Callies, Manley, or Oliver.
For a boosted 6.2L LS build, Callies Compstar H-beam rods are an excellent choice—strong, affordable, and proven. Make sure they're sized for your piston pin diameter and use ARP2000 or better rod bolts torqued to spec with proper lubricant.
Crankshaft
The factory LS3 forged steel crankshaft is perfectly adequate for 700 wheel horsepower. If you're building from an aluminum block LS engine, the crank is already forged. Make sure it's been magnafluxed for cracks, properly balanced with your rotating assembly, and check all bearing surfaces for wear or damage.
For iron block builds using an LQ4 or LQ9, the factory cast cranks can handle this power level, but a forged crank upgrade provides peace of mind and better high-RPM reliability if you plan to shift past 6,500 RPM regularly.
Balancing and Blueprinting
Every single 700+ horsepower engine that leaves our shop gets fully balanced. The entire rotating assembly—pistons, rods, crank, harmonic balancer, and flywheel or flexplate—is balanced as a unit to within 0.5 grams or better. This eliminates vibration, reduces bearing wear, and allows the engine to rev smoothly and safely to higher RPM.
We also blueprint every engine, which means measuring and optimizing all critical dimensions and clearances. Piston-to-wall clearance, ring end gaps, rod and main bearing clearances, and deck height are all set to optimal specifications for the intended use.
Cylinder Heads and Valvetrain
Cylinder Head Selection
At 700 wheel horsepower, you need cylinder heads that flow serious air. For naturally aspirated builds, you'll need ported heads or aftermarket castings. For forced induction, even stock LS3 heads can support 700 wheel horsepower, though porting or aftermarket heads will get you there with less boost and improve efficiency.
Popular choices include:
- Stock LS3/L92 heads (ported): These 260cc rectangle port heads flow 300+ CFM intake and 230+ CFM exhaust when properly ported. Excellent for boosted applications.
- Texas Speed (ported): Their ported LS3 heads are very popular and flow exceptionally well.
- Trick Flow 255 or 270: Aftermarket castings that flow great out of the box and are priced competitively.
- AFR, Brodix, or PRC: High-end aftermarket heads with superior flow and build quality for maximum naturally aspirated or boosted power.
Regardless of which heads you choose, make sure they're assembled with quality valvesprings suitable for your camshaft profile and RPM range. For forced induction, dual valve springs with titanium retainers are recommended to prevent valve float and maintain proper valve control.
Camshaft Selection
The camshaft is where many builders go wrong. You need a cam that matches your combination, intended use, and power delivery goals. For a streetable 700 wheel horsepower LS build, I typically recommend cams in the 230/240-degree range at 0.050-inch lift with 0.600-0.650 inches of valve lift.
For forced induction applications, you don't need as aggressive a cam as naturally aspirated builds because the turbo or supercharger is doing much of the work. Something like a Texas Speed Stage 2 or 3 cam, Comp XFI series, or Brian Tooley Racing Stage 4 cam works beautifully for boosted street/strip cars.
Critical considerations:
- Wider LSA (lobe separation angle) for better vacuum and street manners—typically 112-114 degrees
- Proper spring pressure to prevent valve float without excessive wear
- Degreeing the cam during installation to verify timing events
- Using a quality double-roller timing chain
Forced Induction: Turbo vs Supercharger
To reliably reach 700 wheel horsepower from an LS engine, forced induction is the most practical route. Let's compare the two approaches.
Turbocharger Systems
Turbo systems are incredibly efficient and offer massive power potential. A single Precision 6266, Garrett GTX3582R, or Borg Warner S366 can easily support 700-900 wheel horsepower on an LS engine. Twin turbo setups offer better low-end response and can support even higher power levels.
Advantages:
- Superior efficiency—less heat, better fuel economy when not in boost
- Massive power potential with relatively small turbos
- Adjustable boost levels for pump gas or race fuel
- Cooler intake charge temperatures with proper intercooling
Considerations:
- More complex installation—exhaust manifolds, wastegates, intercooler piping
- Turbo lag (though modern turbos spool quickly)
- Requires proper wastegate control and tuning
- Oil and coolant lines to turbo(s)
Supercharger Systems
Supercharger kits like the Magnuson TVS2300, Whipple 2.9L, or Procharger D1SC are bolt-on friendly and deliver instant throttle response with no lag. For street cars, the linear power delivery is addictive.
Advantages:
- Instant boost response—no lag
- Simpler installation with complete kits available
- Linear, predictable power delivery
- Less tuning complexity compared to turbos
Considerations:
- Parasitic loss—you're using engine power to drive the blower
- Higher intake temperatures (intercooling helps)
- Lower peak efficiency compared to turbos
- Limited boost adjustability on positive-displacement blowers
For Raw Exotics customers building street/strip cars, I often recommend superchargers for their simplicity and drivability. For drag-focused builds or those chasing maximum efficiency, turbos are hard to beat.
Supporting Modifications
Fuel System
At 700 wheel horsepower, fuel delivery is critical. You'll need high-flow fuel injectors (typically 80-100 lb/hr range), a capable fuel pump (like a Walbro 450 or Aeromotive A1000), proper fuel lines, and potentially a returnless-to-return fuel system conversion.
For E85, injector requirements increase significantly—you'll need 20-30% more fuel flow. The advantage is E85's superior knock resistance, allowing more timing and boost safely.
Cooling System
High-horsepower engines generate serious heat. Upgrade to a performance radiator (aluminum with higher core capacity), high-flow water pump, 180-degree thermostat, and consider an upgraded oil cooler. Here in Houston's heat, cooling system upgrades are non-negotiable for reliability.
Oiling System
Stock LS oil pans can be adequate, but for road racing or high-RPM use, an improved oil pan with baffles or a dry sump system prevents oil starvation. Use a high-quality synthetic oil (5W-30 or 10W-30) and change it religiously—I recommend 3,000-mile intervals on high-performance builds.
Assembly Best Practices
Proper assembly is where reliability is built—or destroyed. Here are critical steps we follow at Raw Exotics:
- Cleanliness: Every component is thoroughly cleaned and inspected. No debris, no shortcuts.
- Proper torque specs: Every fastener is torqued to factory or upgraded specifications with proper lubricant.
- Assembly lube: Use quality assembly lube on bearings, cam lobes, lifters, and cylinder walls for initial startup.
- Gasket sealer: Use appropriate sealers sparingly and correctly—more is not better.
- Pre-oiling: Prime the oiling system before first startup to ensure all bearings are lubricated.
- Break-in procedure: Follow proper break-in with varying RPM for the first 30 minutes, then change oil and filter.
Tuning for Reliability
A great engine build can be destroyed by poor tuning. For 700 wheel horsepower on pump gas (93 octane), we typically target:
- Air-fuel ratio: 11.8-12.2:1 under boost
- Ignition timing: Conservative—typically 18-22 degrees total timing under boost depending on octane and boost level
- Boost control: Start low (6-8 psi) and work up gradually, monitoring for knock
- Safety parameters: Knock retard limits, fuel pressure monitoring, coolant temp limits programmed into ECU
We always dyno tune our builds, starting conservatively and gradually increasing power while monitoring all parameters. It's not uncommon to do 15-20 dyno pulls over several hours to properly dial in a 700hp build.
Maintenance and Longevity
A well-built 700hp LS engine can last 100,000+ miles with proper maintenance:
- Oil changes every 3,000 miles with quality synthetic
- Regular spark plug inspection and replacement (every 10,000 miles for boosted applications)
- Cooling system service and inspection annually
- Retorque head studs after initial heat cycles
- Monitor for leaks, unusual noises, or performance changes
- Keep fuel system clean—quality fuel and filters
Budget Expectations
Building a reliable 700hp LS engine isn't cheap, but it's also not as expensive as many exotic platforms. Here's a realistic budget breakdown:
- Core engine (LS3 or similar): $1,500-$3,000
- Forged internals (pistons, rods, bearings): $2,500-$4,000
- Cylinder heads (ported or aftermarket): $2,500-$5,000
- Camshaft and valvetrain: $1,000-$2,000
- Forced induction system: $4,000-$8,000
- Fuel system upgrades: $1,500-$3,000
- Miscellaneous (gaskets, bolts, fluids, etc.): $1,000-$2,000
- Machine work and assembly: $3,000-$5,000
Total: $17,000-$32,000 depending on specific parts choices and whether you're starting from scratch or upgrading an existing engine.
Conclusion
Building a reliable 700 horsepower LS engine is absolutely achievable with the right parts, proper assembly, and conservative tuning. The LS platform's strength, parts availability, and proven track record make it one of the best choices for high-horsepower street builds.
At Raw Exotics, we've built countless LS engines at this power level and beyond. The keys to success are quality components, meticulous assembly, comprehensive tuning, and regular maintenance. Don't cut corners on critical components, and always prioritize reliability over peak numbers.
If you're ready to build a serious LS engine here in Houston, we'd love to help make it happen. Give us a call and let's discuss your project.