Shopping for a 2014–2018 Silverado or Sierra and can’t decide between the 5.3L EcoTec3 V8 and the 6.2L? Here’s the definitive comparison.
5.3L EcoTec3 (LT1/L83):
- 355 HP / 383 ft-lbs torque
- Standard in LT, LTZ trim levels
- AFM/DFM: Yes (cylinder deactivation)
- Direct injection + port injection (Gen V)
- Very common, good fuel economy
- More than adequate for most towing and hauling
6.2L EcoTec3 (L86):
- 420 HP / 460 ft-lbs torque
- Available on LTZ, Z71, High Country, Denali trims
- AFM/DFM: Yes
- Significantly more power and torque
- Premium fuel required (91+ octane recommended)
Real-World Differences:
| Feature | 5.3L | 6.2L |
|---|---|---|
| Horsepower | 355 | 420 |
| Torque | 383 ft-lbs | 460 ft-lbs |
| Fuel | Regular | Premium |
| Max Tow | 11,100 lbs | 12,500+ lbs |
| Resale Value | Standard | Premium |
For Towing:
The 6.2L pulls with noticeably less effort, especially at altitude. If you regularly tow over 8,000 lbs, the 6.2L’s extra torque is the most significant real-world advantage.
For Fuel Economy:
Despite the displacement difference, the 6.2L gets comparable fuel economy to the 5.3L on the highway due to its ability to shift into high overdrive at lower RPM.
The AFM Issue:
Both engines have AFM/DFM cylinder deactivation. Both benefit from a disabler.
Range Technology RA003B AFM/DFM Disabler – Works on both 5.3L and 6.2L EcoTec3 engines.
Bottom Line:
If you can afford the premium for the 6.2L (usually $1,500–$2,500 more), it’s worth it for towing and performance. For everyday use, the 5.3L is more than enough.
Which engine is in your K2XX? Share your experience!