L33 5.3L engine: specs, donor vehicles & swap notes
The L33 is a 5.3 L aluminum-block Generation III engine built 2005–2007, rated 310 hp. It came in 1 vehicle application, including Chevrolet Silverado 1500 4WD/GMC Sierra 1500 4WD.
| Spec | Value |
|---|---|
| RPO | L33 |
| Family | Generation III |
| Years | 2005–2007 |
| Displacement | 5.3 L / 325 ci |
| Horsepower | 310 hp |
| Torque | 335 lb-ft |
| Bore × stroke | 3.78 × 3.622 in |
| Compression | 10.00:1 |
| Block | aluminum |
| AFM/DOD | No |
| VIN 8th digit | B |
| Reluctor | 24x |
| Throttle | Drive-by-wire |
| Stock cam | Unique cam (not shared): @.050 193° duration,.482 in lift, 116° LSA |
| Firing order | 1-8-7-2-6-5-4-3 |
| Oil capacity | 6.0 qt |
| Oil filter | 89017524 / PF48 |
| Spark plug | 12571164 / 41-985 |
| Plug gap | 0.040 in |
| Head casting | 799 / 243 |
- Knock sensor corrosion (water intrusion under intake). Fix: Replace sensors and harness; seal valley; new intake gaskets.
- Oil consumption (rings / PCV). Fix: Monitor level; check PCV and valve seals; rings if excessive.
Aluminum, only available on 4WD extended-cab standard-bed trucks
The L33 specs above are not yet confirmed against GM documents; GM ratings varied by year and vehicle.
How the L33 differs from the other 5.3 L Gen III engines
The L33 is one of the four 5.3 L Gen III engines we list: L33, L59, LM4, LM7. From our engine table:
- Aluminum block. Among the 5.3 L Gen III engines, the L33 shares it with the LM4; the L59, LM7 are iron.
- Compression 10.00:1, the highest of the group.
- Up to 310 hp from the factory, the most of the four 5.3 L Gen III engines we list.
- Built 2005–2007.
Swapping the L33: what to plan for
- Computer: 24x crank, so the L33 matches a Gen III computer (0411/P01 or P59); an E38 or E67 only reads 58x. Throttle and wiring have to suit the computer too. More: how to wire your LS (the full checklist for your engine and computer).
- Drive-by-wire throttle. Plan on the pedal and throttle body that match the L33, 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.
- Rare donor: only available on 4WD extended-cab standard-bed trucks.
- From a truck or SUV (Chevrolet Silverado 1500 4WD/GMC Sierra 1500 4WD): truck accessory drive spacing (the farthest forward of the three), and the factory truck oil pan hangs low; most car swaps need a swap pan. More: accessory drive spacing · oil pans.
Refresh parts for the L33
From our Gen III refresh list, the parts that are specific to the L33. Seals, gaskets and the upgrades worth doing on any Gen III with the engine out are in the full refresh list, next to every torque spec.
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| Part | GM part # | Why for this engine |
|---|---|---|
| Chevrolet Performance Gen III LS knock sensor 12589867 (each) | 12589867 | The L33 has its knock sensors in the valley, under the intake, where water collects. |
| Chevrolet Performance LS Gen III camshaft position sensor 19420911 | 19420911 | 24x engines like the L33 read the cam at the rear of the block. |
From real tunes: 5.3 L on a Gen III computer
What these settings look like in the 472 naturally aspirated pump-gas tunes for 5.3 L engines on Gen III computers (0411/P01, P59) in our tune library (as of 2026-10-15). Every RPO of this size is pooled, not only the L33, and so are all cams, heads and builds: that is why the ranges are wide. 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 900 rpm | 698 rpm | 472 (middle 80%) |
| Warm idle airflow, in gear | 5.6 g/s to 12.7 g/s | 6.8 g/s | 471 (middle 80%) |
| Idle spark (around 800 rpm) | 18° to 25° | 18° | 472 (middle 80%) |
| Power enrichment (PE) lambda | 0.78 to 0.87 | 0.80 | 464 (middle 80%) |
| WOT spark at 5,000 rpm, about 0.9 g/cyl | 11.0° to 26.0° | 15.6° | 472 (middle 80%) |
For starting values matched to your L33'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 L33
Where to find an L33 at the junkyard: 1 vehicle application below. Confirm it from the RPO sticker in the glovebox or the 8th VIN digit (for the L33: B).
| Vehicle | Years |
|---|---|
| Chevrolet Silverado 1500 4WD/GMC Sierra 1500 4WD | 2005–2007 |
Buying a used L33
A used L33 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 L33: B) before you buy.