L8T 6.6L engine: specs, donor vehicles & swap notes
| Spec | Value |
|---|---|
| RPO | L8T |
| Family | Generation V |
| Years | 2020–2026 |
| Displacement | 6.6 L / 401 ci |
| Horsepower | 350–401 hp |
| Torque | 425–464 lb-ft |
| Bore × stroke | 4.065 × 3.858 in |
| Compression | 10.80:1 |
| Block | iron |
| AFM/DOD | No |
| Stock cam | 0.549 in lift, 218° int / 231° exh duration (LT2-derived) |
Iron/Alum. heads, VVT, DI
Specs from secondary sources; GM ratings varied by year and vehicle.
Donor vehicles with the L8T
Where to find one at the junkyard. Confirm with the RPO sticker in the glovebox or the 8th VIN digit.
| Vehicle | Years |
|---|---|
| Chevrolet Express/GMC Savana 2500/3500/4500 | 2021–present |
| Chevrolet Low Cab Forward 3500 HG/4500 HG/5500 HG/5500 XG | 2021–present |
| Chevrolet Silverado HD/GMC Sierra HD | 2020–2026 |
| Crate engine | 2023–present |
Next steps
- Find a cam for the L8T
- Compare every LS donor engine
- Size injectors and fuel pump
- Swap guides by vehicle
Sources