The LS3 and the Gen V LT1 are both 6.2-liter GM small-block V8s with the same bore and stroke, but the LT1 is a newer design with direct injection, variable valve timing, cylinder deactivation and higher compression. In the Corvette, the LS3 is rated at 430 to 436 hp and the LT1 at 455 to 460 hp. The LS3 is simpler and easier to modify; the LT1 makes more power and torque stock and uses less fuel.
LS3 vs LT1 at a glance
| LS3 | LT1 (Gen V) | |
|---|---|---|
| Family | Gen IV LS | Gen V small block |
| Fuel injection | Port injection | Direct injection |
| Cam timing | Fixed | Variable valve timing |
| Cylinder deactivation | No (Corvette and manual Camaro) | Yes (Active Fuel Management) |
| Corvette rating | 430 hp; 436 hp with dual-mode exhaust | 455 hp; 460 hp with performance exhaust |
| Used in | 2008 to 2013 Corvette, 2010 to 2015 Camaro SS manual | 2014 to 2019 Corvette, 2016 and later Camaro SS |
Heads and head flow
Both use rectangular-port style heads, but the LT1’s heads are designed around direct injection, with the injector in the combustion chamber and a different chamber shape. Heads and intakes do not interchange between the two.
Reliability
The LS3 has a strong record and few common faults. The LT1 is also durable, but direct injection can let carbon build up on intake valves over time, and cylinder deactivation lifters are a known wear point on some GM V8s; see LT1 problems.
Which is better for boost?
Both take a supercharger well with the right kit and fuel system. Port injection on the LS3 makes adding fuel straightforward; the LT1’s direct-injection pump limits how much fuel can be added without upgrades. Kits are engine-specific: see LS3 supercharger kits and LT1 supercharger kits, plus fuel injector sizing.
Torque and drivability
The LT1’s direct injection and higher compression give it noticeably more low- and mid-range torque than the LS3, so it feels stronger in everyday driving even before the higher peak rating. Its variable valve timing also broadens the power band. The LS3 is happiest at higher rpm and responds well to camshaft changes, which is one reason it remains popular for builds.
Fuel economy
Cylinder deactivation lets the LT1 run on four cylinders at light load, which improves highway fuel economy. The LS3 in Corvettes and manual Camaros runs on all eight cylinders all the time.
Swaps
LS3s are a common swap engine because of their simple wiring and wide parts support; LT1 swaps need the engine’s own controller and fuel system. See LS swap guide and LS engines.
Related
See LS2 vs LS3, C6 vs C7 Corvette and Corvette generations.
More guides: LS swap transmission options.
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