Chevrolet LS Gen III/IV LS1-LS9 - the world's most common V8 swap
Modern small-block architecture from 1997. All-aluminium block, 6-bolt main caps, TTY bolts throughout, coil-on-plug per cylinder. The heart of the C5/C6 Corvette, Camaro SS, CTS-V and a growing number of Volvo 240, BMW E30 and Saab 9-3 V8 swaps.
The LS is not a modernised Gen I. It is a new engine family. In 1997 GM launched a completely new V8 architecture. All-aluminium block (most of them), 6-bolt main caps with side bolts, TTY bolts throughout, coil-on-plug per cylinder and a 24X reluctor crank. Many still call them "small-block" because they share the 4.40-inch bore spacing and bellhousing pattern - but GM and most engine builders treat the LS as a separate family.
We rebuild the whole LS family from the LS1 to the LS9, plus the truck variants (LM7, LQ4, LQ9, LY6, L96). The LS3 is the one we see most - usually as a donor for a V8 swap into a Volvo 240, BMW E30, Saab 9-3 or another compact car chasing horsepower per unit of cost. For general service information, see our V8 engine reconditioning page.
All LS variants
The LS family spans 25+ variants across two generations. Here are the ones we see.
Gen III LS (1997-2007)
| Variant | Displ. | Bore × Stroke | Block | HP | Common application |
|---|---|---|---|---|---|
| LS1 | 5.7L (346 ci) | 3.898 × 3.622″ | Aluminium | 305-350 | C5 Corvette, 4th-gen Camaro/Firebird |
| LS6 | 5.7L (346 ci) | 3.898 × 3.622″ | Aluminium | 385-405 | C5 Z06, Cadillac CTS-V Gen I |
| LR4 | 4.8L (293 ci) | 3.78 × 3.27″ | Cast iron | 255-285 | Tahoe, Yukon, Silverado, Express |
| LM7 | 5.3L (325 ci) | 3.78 × 3.62″ | Cast iron | 270-295 | Silverado, Tahoe - the junkyard-LS staple |
| LM4 | 5.3L (325 ci) | 3.78 × 3.62″ | Aluminium | 290 | TrailBlazer EXT, SSR (short production run) |
| LQ4 | 6.0L (364 ci) | 4.00 × 3.62″ | Cast iron | 300-335 | Silverado HD, Hummer H2 - the budget swap favourite |
| LQ9 | 6.0L (364 ci) | 4.00 × 3.62″ | Cast iron | 345 | Cadillac Escalade, Silverado SS - VortecMAX |
Gen IV LS (2005-2020)
| Variant | Displ. | Bore × Stroke | Block | HP | Common application |
|---|---|---|---|---|---|
| LS2 | 6.0L (364 ci) | 4.00 × 3.622″ | Aluminium | 400 | C6 Corvette base, GTO, TrailBlazer SS, CTS-V Gen I |
| LS3 Popular | 6.2L (376 ci) | 4.065 × 3.622″ | Aluminium | 426-436 | 08-13 Corvette, 10-15 Camaro SS, Pontiac G8 GXP |
| L99 | 6.2L (376 ci) | 4.065 × 3.622″ | Aluminium | 400 | Camaro SS automatic - an LS3 with AFM |
| LS7 Hand-built | 7.0L (427 ci) | 4.125 × 4.00″ | Aluminium (sleeved) | 505 | C6 Z06, Camaro Z/28 - titanium rods |
| LS9 Supercharged | 6.2L (376 ci) | 4.065 × 3.622″ | Aluminium | 638 | C6 ZR1 - Eaton TVS2300 dry-sump |
| LSA Supercharged | 6.2L (376 ci) | 4.065 × 3.622″ | Aluminium | 556-580 | CTS-V Gen II, Camaro ZL1 - Eaton TVS1900 |
| LY6 / L96 | 6.0L (364 ci) | 4.00 × 3.622″ | Cast iron | 361 | Silverado HD, Express - VVT + flex-fuel |
| L92 / L94 | 6.2L (376 ci) | 4.065 × 3.622″ | Aluminium | 403-420 | Cadillac Escalade, Hummer H2, Yukon Denali |
Common to all LS engines: 9.240″ deck height, 4.40″ bore spacing, 6-bolt main caps with side bolts, TTY bolts everywhere, coil-on-plug per cylinder, 24X reluctor crank, 16-bolt intake pattern.
Torque specs for all LS Gen III/IV
Verified against GM's factory Engine Mechanical manual (4.8 / 5.3 / 6.0L LS truck block) and the GM Service Manual for the 6.2L LS3. ALL LS bolts are TTY - replace them at every teardown.
Topplock (M11 TTY)
Ramlager (6-bolt main, side-bolts)
Connecting rod bolts (TTY)
OBS - LS rod bolts: Powdered-metal rods are fine up to around ~500 hp. Above that, switch to upgraded racing rod bolts at 65 ft-lbs or 0.0050″-0.0060″ stretch. The factory bolts are designed for single use and have a limited safety margin under boost. We fit a racing-grade fastener kit as part of V8 engine reconditioning.
Harmonic balancer & flywheel
Intake, exhaust & lubrication system
Cylinder head specs by variant (most common)
| Variant | Comb. chamber | Intake port | Exhaust port | Intake valve | Exhaust valve |
|---|---|---|---|---|---|
| LS1 | 67 cc | 200 cc | 70 cc | 2.000″ | 1.550″ |
| LS6 | 65 cc | 210 cc | 75 cc | 2.000″ | 1.550″ |
| LS3 / L92 | 68 cc | 257 cc (rectangular port) | 87 cc | 2.165″ | 1.590″ (sodium-filled) |
| LS7 | 70 cc CNC | 259 cc (raised square, CNC) | 86 cc (D-port, CNC) | 2.205″ (titanium) | 1.610″ (sodium-filled) |
Factory cam specs (LS1 by year)
| Model/year | Int. dur @.050 | Exh. dur @.050 | Int. lift | Exh. lift | LSA |
|---|---|---|---|---|---|
| 1997-99 Corvette LS1 | 199° | 207° | 0.472″ | 0.479″ | 117° |
| 2000 Corvette LS1 | 198° | 209° | 0.500″ | 0.500″ | 115.5° |
| 2001-04 Corvette LS1 | 196° | 208° | 0.467″ | 0.479″ | 116° |
| 1998-00 Camaro/Firebird | 198° | 209° | 0.498″ | 0.497″ | 119.5° |
| 2001-02 Camaro/Firebird | 196° | 208° | 0.467″ | 0.479″ | 116° |
Common faults on the LS Gen III/IV
AFM / DOD lifter collapse
Gen IV 5.3 / 6.2 • High- Symptoms
- Ticking from the top of the engine, P0306-P0308 cylinder misfire codes, oil consumption, "reduced power" mode.
- Cause
- Active Fuel Management uses solenoids to bleed oil to 4 lifters - the cylinders shut down to V4 at cruise. The lifters collapse after 100,000+ km. It affects the L99, LH6, LY5, LC9, LMG and L76 - all Gen IV engines with AFM.
Fix: An AFM-delete kit + a non-AFM cam + new lifters + an ECU update. This is the most common LS job right now. We carry out cam grinding to our own profile and update the software.
Oljeförbrukning på 5.3L AFM (LMG, LC9)
Gen IV 5.3 • Medium- Symptoms
- 1 qt of oil per 1500 km, blue smoke under acceleration, oil mist from the PCV system.
- Cause
- AFM-specific piston rings + an oil-separator problem in the PCV system. Common on the 5.3L with AFM after 100,000 km.
Valve spring failure (LS3/LS6 high RPM)
Performance use • Medium- Symptoms
- Misfire over 6,500 RPM, valve float, broken valves at extreme RPM.
- Cause
- The original LS3 springs are designed for the OEM 6,500 RPM. A cam upgrade + high-RPM use fatigues them quickly.
Fix: Beehive-upgraded valve springs as standard when changing the cam on an LS3. We replace the springs as part of cylinder head reconditioning.
Cracked piston cyl #7 (LS7 specifik)
LS7 high RPM • High- Symptoms
- Sudden loss of power, P0307 (cylinder 7 misfire), compression loss on cylinder 7.
- Cause
- The LS7's hypereutectic cast piston has a design weakness on cylinder 7 under sustained high RPM. It shows up most often on street-tracked LS7s. The hand-built LS7 from Wixom has the problem documented in a GM TSB.
Fix: Forged pistons + upgraded racing rod bolts. Standard if you plan to run the LS7 hard on a regular basis. Requires cylinder boring and balancing of the new components.
Rod knock på 100 000+ km truck-LS
Wear • Medium- Symptoms
- Knock-knock-knock under load, low oil pressure.
- Cause
- Natural wear on the powdered-metal rods + bearings. Made worse by neglected oil changes (the 5.3L AFM needs them more often).
LS tuning - why the LS is the easiest engine in the world to tune
Coil-on-plug, plug-and-play sensors and modern controls make LS tuning beginner-friendly compared with a Gen I carburettor.
- 1
Bolt-on (LS3 / LS1)
Long-tube headers + cat-back + cold air intake + ECU tune. LS3 = +90-110 hp easily.
525-575 hk (LS3) - 2
Cam-only swap
Performance camshaft grinding + double-roller chain + beehive springs + ECU tune. LS3 = 575-625 hp. We grind our own cam profiles in our camshaft grinding service.
575-625 hk (LS3) - 3
Heads + cam
CNC-ported aluminium heads + a bigger cam + 1.85 rockers. A common serious build. We carry out porting and cylinder head reconditioning in-house.
650-750 hk (LS3) - 4
Forced induction (turbo or supercharger)
Single or twin-turbo, or a bolt-on positive-displacement supercharger. 6-7 psi easily makes 800 hp on stock bearings. We upgrade turbo systems.
800-1200 hk
LS swaps in road cars
We rebuild LS engines for swap projects. We do not build the engine subframe or driveline ourselves, but we deliver a finished long-block that is ready to fit with your chosen accessory pack.
Most common swap cars: Volvo 240, 740, Amazon, Saab 9-3, Mercedes W123, BMW E30/E36. Commercial swap-bracket kits are available for these on the aftermarket. We deliver a finished long-block that can be fitted with your chosen accessory pack - see our V8 reconditioning packages.
Choosing a donor LS by budget
| Budget | Donor engine | Stock hp | HK post-cam | Used price |
|---|---|---|---|---|
| Budget | LM7 5.3L (Tahoe/Silverado) | 270-295 | 400-450 | 8 000-15 000 kr |
| Budget+ | LQ4 6.0L (Silverado HD) | 300-335 | 500-550 | 12 000-20 000 kr |
| Mid | LS1 5.7L (Camaro / Corvette) | 305-350 | 425-475 | 25 000-40 000 kr |
| Performance | LS3 6.2L (Camaro SS / Corvette) | 426-436 | 525-625 | 40 000-65 000 kr |
| Extreme | LS7 7.0L (Z06) | 505 | 650+ | 80 000+ kr |
Tips: Truck-LS engines (LM7, LQ4, LQ9) are often cheaper than Camaro/Corvette LS engines because they are more plentiful in US junkyards. Mechanically the same bottom end. The truck heads are fairly poor, though - budget for a head swap to LS6 or aftermarket CNC-ported aluminium heads. We carry out cylinder boring, crankshaft grinding and balancing on the donor LS to bring it up to quality standard.
LS rebuild or swap?
We rebuild the whole LS family. Call us or send in a quote request. Reply within 24 hours.