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LQ4 vs LQ9: what's the difference?
Both are 6.0 L (364 ci) iron-block Gen III truck engines with the same 4.000 in bore and 3.622 in stroke. The differences:
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| LQ4 | LQ9 | |
|---|---|---|
| Years | 1999–2008 | 2002–2007 |
| Power | 300–335 hp | 345 hp |
| Torque | 355–375 lb-ft | 380 lb-ft |
| Compression | 9.40:1 | 10.00:1 |
| VIN 8th (truck) | U | N |
| Typical donors | Silverado/Sierra 1500HD/2500/2500HD/3500, Suburban 2500 | Cadillac Escalade (AWD/2WD/EXT/ESV), Silverado SS, GMC Sierra Denali |
The LQ9's higher compression (10.00:1 vs 9.40:1) accounts for much of its extra power. Early LQ4s (1999–2000) had iron heads. Both are common, inexpensive swap engines.
Swapping an LQ4 or LQ9: what to plan for
Swapping the LQ4: what to plan for
- Computer: 24x crank, so the LQ4 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 (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 (Chevrolet Silverado/GMC Sierra 1500HD/2500/2500HD/3500, GMC Sierra C3, GMC Sierra Denali, Chevrolet Suburban 2500/GMC Yukon XL 2500 and 2 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 2500/3500, Chevrolet W-Series/GMC W-Series/Isuzu NPR): the accessory drive and intake differ from the pickups; check what comes with it before you plan brackets (not confirmed in our data).
Swapping the LQ9: what to plan for
- Computer: 24x crank, so the LQ9 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 2002; drive-by-wire 2003-2007. 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 AWD, Cadillac Escalade 2WD, Cadillac Escalade EXT, Cadillac Escalade ESV and 2 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.