LM7 5.3L engine: specs, donor vehicles & swap notes
The LM7 is a 5.3 L iron-block Generation III engine built 1999–2007, rated 270–295 hp. It came in 6 vehicle applications, including Cadillac Escalade 2WD, Chevrolet Avalanche 1500.
| Spec | Value |
|---|---|
| RPO | LM7 |
| Family | Generation III |
| Years | 1999–2007 |
| Displacement | 5.3 L / 325 ci |
| Horsepower | 270–295 hp |
| Torque | 315–335 lb-ft |
| Bore × stroke | 3.78 × 3.622 in |
| Compression | 9.49:1 |
| Block | iron |
| AFM/DOD | No |
| VIN 8th digit | T |
| Reluctor | 24x |
| Throttle | Cable 1999-2002; drive-by-wire 2003-2007 pickups/SUVs (vans cable through 2006) |
| Stock cam | 190/191 duration,.466/.457 lift, 114 LSA, 112/116 timing. |
| Firing order | 1-8-7-2-6-5-4-3 |
| Oil capacity | 6.0 qt (5.7 L) |
| Spark plug | 41-985 Iridium |
| Plug gap | 0.040 in (1.0 mm) |
| Head casting | 706 / 862 |
- 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.
Iron/Alum. heads
The LM7 specs above are not yet confirmed against GM documents; GM ratings varied by year and vehicle.
How the LM7 differs from the other 5.3 L Gen III engines
The LM7 is one of the four 5.3 L Gen III engines we list: L33, L59, LM4, LM7. From our engine table:
- Iron block. Among the 5.3 L Gen III engines, the LM7 shares it with the L59; the L33, LM4 are aluminum.
- Compression 9.49:1, the lowest of the group.
- Up to 295 hp from the factory (2nd of the four 5.3 L Gen III engines we list; the group tops out at 310 hp).
- Built 1999–2007.
Swapping the LM7: what to plan for
- Computer: 24x crank, so the LM7 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).
- Throttle depends on the year: Cable 1999-2002; drive-by-wire 2003-2007 pickups/SUVs (vans cable through 2006). Drive-by-wire needs the matching pedal and throttle body; the base Holley Terminator X is cable-only (the X Max does drive-by-wire).
- From a truck or SUV (Cadillac Escalade 2WD, Chevrolet Avalanche 1500, Chevrolet Silverado/GMC Sierra 1500, Chevrolet Suburban/GMC Yukon XL 1500 and 1 more): 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.
- From a van or work truck (Chevrolet Express/GMC Savana 1500/2500): the accessory drive and intake differ from the pickups; check what comes with it before you plan brackets (not confirmed in our data).
Refresh parts for the LM7
From our Gen III refresh list, the parts that are specific to the LM7. 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 4.8L & 5.3L truck head gasket | 12575329 | Listed for the LM7; a new gasket goes on any time the heads come off. |
| Stock cylinder head bolt set, 1997-2003 LS (unequal-length design) | 12498545 | LM7 engines built through 2003 use the first-design, unequal-length bolts. Single use. Engines built from 2004 take the second-design, equal-length set (in the Gen IV list). |
| Chevrolet Performance Gen III LS knock sensor 12589867 (each) | 12589867 | The LM7 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 LM7 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 LM7, 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 LM7'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 LM7
Where to find an LM7 at the junkyard: 6 vehicle applications below. Confirm it from the RPO sticker in the glovebox or the 8th VIN digit (for the LM7: T).
| Vehicle | Years |
|---|---|
| Cadillac Escalade 2WD | 2002–2005 |
| Chevrolet Avalanche 1500 | 2002–2006 |
| Chevrolet Express/GMC Savana 1500/2500 | 2003–2007 |
| Chevrolet Silverado/GMC Sierra 1500 (and 1999–2000 2500) | 1999–2007 |
| Chevrolet Suburban/GMC Yukon XL 1500 | 2000–2006 |
| Chevrolet Tahoe/GMC Yukon | 2000–2006 |
Buying a used LM7
A used LM7 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 LM7: T) before you buy.
Next steps
- Plan a swap with the LM7
- Find a cam for the LM7
- What the LM7 tune needs
- Compare every LS donor engine
- Size injectors and fuel pump
- LS torque specs
- Swap guides by vehicle