LS4 5.3L engine: specs, donor vehicles & swap notes
The LS4 is a 5.3 L aluminum-block Generation IV engine built 2005–2009, rated 300–303 hp. It came in 4 vehicle applications, including Pontiac Grand Prix GXP, Chevrolet Impala SS. Things to know: it has AFM, so an aftermarket cam means a full AFM delete.
We may earn a commission when you buy through links on this page.
| Spec | Value |
|---|---|
| RPO | LS4 |
| Family | Generation IV |
| Years | 2005–2009 |
| Displacement | 5.3 L / 325 ci |
| Horsepower | 300–303 hp |
| Torque | 323 lb-ft |
| Bore × stroke | 3.78 × 3.622 in |
| Compression | 10.00:1 |
| Block | aluminum |
| AFM/DOD | Yes |
| VIN 8th digit | C |
| Reluctor | 2005-2006 (Impala SS, Monte Carlo SS, Grand Prix GXP, LaCrosse Super): 24x; 2007-2009 (Impala SS, Monte Carlo SS): 58x |
| Throttle | Drive-by-wire (all years) |
| Stock cam | 2005-2007 LS4: Cam PN 12569525; duration 193°/193° @.050 in. int./exh.; valve lift 0.482"/0.482" int./exh.; 114° LSA; 3-bolt gear, 1x; AFM Yes, VVT No; 2007-2009 LS4: Cam PN 12625436; duration 196°/201° @.050 in. int./exh.; valve lift 0.481"/0.481" int./exh.; 116°+2 LSA; 1-bolt gear, 4x; AFM Yes, VVT No |
| Firing order | 1-8-7-2-6-5-4-3 |
| Oil capacity | 6.0 qt |
| Oil filter | 89017524 / PF48 |
| Spark plug | 12609877 / 41-985 |
| Plug gap | 0.040 in |
| Head casting | 799 / 243 |
- Displacement on Demand (DOD/AFM) lifter problems. Fix: Tune out DOD; AFM delete kit.
- Excess oil consumption (DOD-related). Fix: Tune out DOD; keep oil topped off.
- Ticking at startup (lifter noise). Fix: Replace lifters; inspect cam lobes.
Aluminum, AFM, FWD
The LS4 specs above are not yet confirmed against GM documents; GM ratings varied by year and vehicle.
How the LS4 differs from the other 5.3 L Gen IV engines
The LS4 is one of the eight 5.3 L Gen IV engines we list: LC9, LH6, LH8, LH9, LMF, LMG, LS4, LY5. From our engine table:
- Aluminum block. Among the 5.3 L Gen IV engines, the LS4 shares it with the LC9, LH6, LH8, LH9; the LMF, LMG, LY5 are iron.
- AFM (cylinder deactivation): yes. Same as the LC9, LH6, LMG, LY5; the LH8, LH9, LMF don't.
- Compression 10.00:1, the highest of the group.
- Up to 303 hp from the factory (6th of the eight 5.3 L Gen IV engines we list; the group tops out at 320 hp).
- No VVT (the LH9 has it; the LC9 has it (2009 and 2010 XFE trucks; other years Unconfirmed); the LMF has it on some model years).
- Built 2005–2009.
Swapping the LS4: what to plan for
- Computer: check your crank reluctor first. The LS4 left the factory with either one (2005-2006 (Impala SS, Monte Carlo SS, Grand Prix GXP, LaCrosse Super): 24x; 2007-2009 (Impala SS, Monte Carlo SS): 58x). An E38 or E67 only reads 58x, and there is no box that turns 24x into 58x. The crank pattern is only the first match: the cam sensor, knock sensors, throttle and wiring have to suit the computer too. More: how to wire your LS (pick your engine and computer for the full checklist).
- Drive-by-wire throttle. Plan on the pedal and throttle body that match the LS4, and a computer that runs drive by wire; the base Holley Terminator X is cable-only (the X Max does drive-by-wire). More: drive-by-wire pinout.
- AFM: a stock-cam LS4 can have AFM turned off in the tune; an aftermarket cam means a full AFM delete (non-AFM lifters and trays, a non-AFM valley cover, the tune). More: LS cam swap guide.
- Came only in transverse front-wheel-drive cars. Its oil pan, accessory drive and front-end parts were built for that layout, so plan to replace them for a rear-drive swap. Which parts carry over is not confirmed in our data: check fitment before you buy.
Refresh parts for the LS4
From our Gen IV refresh list, the parts that are specific to the LS4. Seals, gaskets and the upgrades worth doing on any Gen IV with the engine out are in the full refresh list, next to every torque spec.
| Part | GM part # | Why for this engine |
|---|---|---|
| LSXceleration Gen IV LS knock sensor 28-23730 | 28-23730 | The LS4 has its knock sensors on the side of the block. |
| GM Gen IV camshaft position sensor 12591720 (58x engines) | 12591720 | 58x LS4: the cam sensor lives in the front cover. |
| Chevrolet Performance 58x crankshaft position sensor 12703627 | 12703627 | 58x LS4: the crank sensor is behind the starter. |
| GM oil pressure screen/filter 12585328 (AFM valley cover) | 12585328 | On 2007-and-later AFM V8s (check your LS4's build year): Clogged screen starves the sender and causes false low-pressure codes on AFM engines. |
| Genuine GM 12610141 valley cover gasket (LS2/LS3, no AFM/DOD) | 12610141 | Needed if you delete AFM on the LS4 with a non-AFM valley cover. |
What real 5.3 L Gen IV (E38) tunes run
What these settings look like in the 192 naturally aspirated pump-gas tunes for 5.3 L engines on an E38 computer in our tune library (as of 2026-10-15). These files do not record which 5.3 L it was (LC9, LMG, LY5 or another) or which vehicle, so this is the 5.3 L Gen IV (E38) naturally aspirated pool, not one RPO. Most files have no stock or aftermarket cam label, so stock and aftermarket stay in one table. The ranges are wide because every cam and build in that pool is included. Use them to spot a value that is far outside what works, not as your numbers.
| Setting | Range | Median | Tunes |
|---|---|---|---|
| Hot idle target | 525 rpm to 800 rpm | 535 rpm | 192 (middle 80%) |
| Warm idle airflow, in gear | 6.0 g/s to 10.5 g/s | 6.8 g/s | 192 (middle 80%) |
| Idle spark (around 800 rpm) | 16° to 20° | 18° | 191 (middle 80%) |
| Power enrichment (PE) lambda | 0.76 to 0.85 | 0.78 | 184 (middle 80%) |
| WOT spark at 5,000 rpm, about 0.9 g/cyl | 13.0° to 22.5° | 14.5° | 192 (middle 80%) |
For starting values matched to your LS4's cam, injectors and fuel, use the turn-on tune builder. Always finish on a dyno, and read our safe tuning limits before any wide-open pass.
Donor vehicles with the LS4
Where to find an LS4 at the junkyard: 4 vehicle applications below. Confirm it from the RPO sticker in the glovebox or the 8th VIN digit (for the LS4: C).
| Vehicle | Years |
|---|---|
| Buick LaCrosse Super | 2008–2009 |
| Chevrolet Impala SS | 2006–2009 |
| Chevrolet Monte Carlo SS | 2006–2007 |
| Pontiac Grand Prix GXP | 2005–2008 |
Buying a used LS4
A used LS4 has no single part number, so this page does not link a search. Confirm the engine from the RPO sticker or the 8th VIN digit (for the LS4: C) before you buy.