The L99 is a 6.2L, Gen. 4, small block engine used in the Chevy Camaro SS from 2010-2015. The information listed here is for a stock L99 engine.
Mechanically similar, General Motors’ LS and LS-based Vortec engines wound up on almost every branch of the GM family tree: Chevy, Pontiac, GMC, Cadillac, Buick—heck, even Saab, Hummer, and Isuzu got some LS love.
Since LS and Vortec engines are so common, they’ve become the go-to performance and swap engines of the modern era.
These motors are capable of making a lot of horsepower, and respond well to upgrades like turbos, superchargers, high-flow cylinder heads, intake systems, cams, and nitrous oxide.
[Looking to upgrade your L99 engine? Check out L99 6.2L Engine Upgrade Guide: Expert Advice for L99 Mods to Maximize Performance.]
The aftermarket is strong, crate engines are available, and used motors are often cheaply sourced through junkyards.
Summit Racing has created a series of comprehensive guides for each engine in the LS family, so engine builders and tuners can have a handy reference for their projects.
This specific guide is for the GM L99 6.2L engine.
You can find more LS engine spec guides and LS-related information here.
(Summit Racing’s Paul Spurlock and Brian Nutter contributed to this article.)
…
L99 6.2L Engine Specs
L99 Performance Specifications
| Engine Ratings | |
|---|---|
| Compression Ratio | 10.4:1 |
| Horsepower Rating | 400 hp |
| Torque Rating | 410 ft./lbs. |
L99 Applications
| VIN 8th Digit | Year | Make | Model |
|---|---|---|---|
| J | 2010-15 | Chevrolet | Camaro SS (w/ auto trans.) |
L99 Engine Blocks
| L99 Block Specs | |
|---|---|
| Casting Number | 12584724 |
| Material | Aluminum |
| Displacement | 6.2L / 376 c.i.d. |
| Bore Dia. | 4.065 in. |
| Stroke | 3.622 in. |
| Deck Height | 9.240 in. |
| Bore Spacing | 4.400 in. |
| Thrust Bearing Location | #3 Main |
| Main Cap Style | 6-Bolt |
| Main Housing Bore Dia. | 2.751 in. |
| Cam Housing Bore Dia. | Bore 1/5 = 2.346, Bore 2/4 = 2.326, Bore 3 = 2.307 |
| Cam-to-Crank Centerline | 4.914 in. |
L99 Rotating Assembly
| L99 Rotating Assembly Specs | |
|---|---|
| Piston Material | Hypereutectic Cast Aluminum Alloy |
| Piston Style | Flat Top with Valve Reliefs |
| Piston Volume | +3cc |
| Wrist Pin Dia. | 0.9431 in. (full floating) |
| Connecting Rod Material | Powdered Metal |
| Connecting Rod Style | I-Beam |
| Connecting Rod Length | 6.098 in. |
| Connecting Rod Housing Bore | 2.225 in. |
| Connecting Rod Bolts | M9 x 1 x 43 |
| Connecting Rod Part Number | 12649190 |
| Crankshaft Material | Cast Iron |
| Crankshaft Part Number | 12588612 |
| Crankshaft Main Journal | 2.559 in. |
| Crankshaft Rod Journal | 2.100 in. |
| Reluctor Wheel | 58x |
L99 Cylinder Heads
| L99 Cylinder Head Specs | |
|---|---|
| Casting Numbers | 823 |
| Material | Aluminum |
| Combustion Chamber Volume | 70cc |
| Intake Port Shape | Rectangle |
| Intake Runner Volume | 257cc |
| Exhaust Port Shape | D-Port |
| Exhaust Runner Volume | 87cc |
| Intake Valve Diameter | 2.165 in. |
| Exhaust Valve Diameter | 1.590 in. |
| Cylinder Head Bolt Style | Torque to Yield (TTY) |
| Cylinder Head Bolt Size | (10) M11 x 2 x 100, (5) M8 x 1.25 x 45 |
L99 Cam Specifications
| L99 Camshaft Specs | |
|---|---|
| Camshaft Part Number | 12623066 |
| Duration @ .050 in. (int./exh.) | 195°/201° |
| Valve Lift (int./exh.) | 0.500 in./.492 in. |
| Lobe Separation | 115° |
| Cam Gear Attachment | 1-Bolt |
| Cam Gear Poles | 4x |
| Active Fuel Management (AFM) | Yes |
| Variable Valve Timing (VVT) | Yes |
L99 Valvetrain
| L99 Valvetrain Specs | |
|---|---|
| Lifter Style | Hydraulic Roller |
| Lifter Link Style | Plastic Lifter Tray |
| Lifter Body Diameter | 0.842 in. |
| Pushrod Length | 7.385 in. |
| Rocker Arm Mounting Style | Pedestal |
| Rocker Arm Style | Die-Cast, Roller Fulcrum |
| Rocker Ratio | 1.7 |
| Rocker Offset | Intake Rocker |
| Valve Spring Style | Beehive |
| Valve Spring Color | Natural |
| Valve Angle | 15 Degrees |
| Intake Valve Material | Steel – Solid Stem |
| Intake Valve Dia. | 2.165 in. |
| Exhaust Valve Material | Steel – Solid Stem |
| Exhaust Valve Dia. | 1.590 in. |
| Timing Chain Guide Style | Spring-Loaded Tensioner |
Other Key L99 Specs
| Throttle Body, Fuel Injectors, Oil Pan Specs & More | |
|---|---|
| Intake Manifold | Car-style |
| Throttle Body | 90mm, 4-bolt, gold blade |
| Throttle Control | Electronic (drive-by-wire) |
| Fuel Injector Part Number | 12576341 |
| Fuel Injector Flow | 42 lbs./hr. at 58 psi |
| Flex Fuel Capable (E-85) | No |
| Fuel Injector Length (between O-Rings) | 1.500 in. |
| Fuel Injector Connector | EV6-USCAR |
| PCM | E38 |
| Crankshaft Reluctor Ring | 58x |
| Camshaft Sensor | Front mount, 4x |
| Oil Pan Sump Location | Center sump |
| Oil Pump | High volume (1.25 c.i. per rev. @ 33 psi) |
…
NOTE: You can find engine specs and detailed engine upgrade advice for every LS and LS-based Vortec truck engine in one place: The Definitive Guide to LS Engine Specs and LS Engine Upgrades.
[…] [Every L99 engine spec you’ll need can be found here: L99 6.2L Engine Specs: Performance, Bore & Stroke, Cylinder Heads, Cam Specs & More.] […]
[…] L99 6.2L Engine Specs: Performance, Bore & Stroke, Cylinder Heads, Cam Specs & More […]
I have a 2012 Camaro SS L99 6.2L. I recently had one of the AFM lifters collapse and I am replacing all of the lifters with LS7 type. I am deleting the AFM from the setup but want to maintain VVT. The cam specs you have listed for the L99 & the LS3 have the exact same model # 12623066. If this is the case, I shouldn’t have to replace the cam. The LS3 does not have AFM or VVT, but the L99 has both. But if they are both using the exact same cam I should be fine, correct?
You are not fine Ronald. They also don’t list the valve lift specs quite right. They are different for the AFM cylinders and the non-AFM cylinders. The cams ARE different too, if you try using an AFM cam on a non-AFM motor and vise versa, you will get a hard misfire guaranteed. I’ve done it. Now if you get an LS3 cam and delete AFM and tune it, your probably ok.
As of today according to GM service information the lift specs for an 11 Camaro L99
Valve Lift – Exhaust – Non Active Fuel Management
12.52 mm
0.493 in
•Valve Lift – Exhaust – Active Fuel Management
12.74 mm
0.501 in
•Valve Lift – Intake – Non Active Fuel Management
12.69 mm
0.499 in
•Valve Lift – Intake – Active Fuel Management
12.91 mm
0.508 in
I have a 2010 ss camaro I was wondering if some or the 2010 or the earlyer modle camaro did they not come win afm because mine 2010 seems like it don’t have it or note it is a automatic car ss thanks.
If its a 2010 auto, it came with the L99 with AFM. If someone has replaced the motor, no telling what the may have put in. A previous owner may have disable the system on the original L99.
vrey helful m question is does the vvt dekete kit work nd for the AFM lifters i have no ifed could you educate me>
Will W-pistons fit on J-engines? (W=LS3 w man. J=L99 w auto). Will rebuild a Camaro 2012 2SS with auto and delete AFM.
All 6.2 motors use same 4.065 dia. pistons. Compression ratio is the same for LS3 & L99 motors. So you should be fine.
hello have a 2011 camaro ss, want to make some more HP. have a chabce to purchase a supercharger kit off of a zli whole kit with cam, and intercooler would also do a cam up grade , put will i have to much compression ? any suggestion would help thanks. I also am rebuilding a 6.2 in a 2016 gmc sierra , that one ran out of oil, but thinking of getting rid of AFM and maybe a cam up grade will be my new to me daily drive and mild pulling of jet ski’s and pontoon very short distance,
I have a 2012 camaro ss 6.2 it’s stock cam stock stings stock heads stock rings, upgraded injectors,it has a 74mm turbo with intercooler it makes 530 rear wheel on the dyno. Just saying