LS6 Family: GM Releases Power Specs for its New Sixth Gen Small Block V8s for Silverado, Sierra

When Chevrolet pulled the silk off the 2027 Corvette Grand Sport/GSX in March, it was a monumental occasion. The world wasn’t only treated to the next pair of cogs in the C8 Corvette performance onslaught, it got its first peek at an all-new generation of Chevy’s timeless Small-Block V8 for only the 6th time since 1955. At 6.7L, 535 horsepower, and 520 lb-ft. of torque, the Grand Sport’s LS6 was the most impressive opening salvo in the much-celebrated history of GM’s bread and butter V8.

After it’s ‘grand’ entrance, it didn’t take long for the second act to hit the stage. GM revealed the next two members of the Sixth Gen V8 family as the powerplants for the upcoming Silverado and Sierra 1500 trucks in June. While fans cheered on the return of historic 5.7 and 6.6L displacements, the specs everyone wanted to know, like power and twist, were conspicuously absent from the initial media packets for the half-ton pickups. As of Thursday morning, the wait is over. We finally have the official SAE ratings for the Grand Sport’s more utilitarian twins.

The new base 5.7L V8 has been dubbed “L76,” and with 402 horsepower, it lands among the two greatest performance 350s ever minted; the C4 Corvette ZR-1’s DOHC LT5 and the C5 Z06’s time stewarding the LS6 nomenclature, which both hit their respective peaks at 405 ponies. Where it greatly exceeds both ‘Vette legends, though, is with its stonking 428 torques – vs. 385 for the C4 and an even 400 for the C5. More importantly, the L76 outmuscles Ram’s standard Hemi V8 of the same displacement (395 HP, 410 lb-ft.) and the only V8 available in non-Raptor Ford F-150s (the 400 horse, 410 torque 5.0).

Chevrolet’s Next-Generation Light-Duty Powertrain Quick Reference

In slightly disappointing news, the 6.6L “L78” didn’t make it to 500 horsepower, but luckily, it did surpass 500 lb-ft. – if only barely. Official numbers for the optional V8 are 481 HP and 501 lb-ft. Again, those numbers are best in class for free-breathing V8s, superseding the 470/455 rating of Ram’s 6.4L Hemi. It also stacks up nicely against the high-output twin-turbo “EcoBoost” V6 found in higher-trim F150s, easily besting its 450 horsepower and barely falling short of its 510 lb-ft. all while sounding much better, delivering a nice linear power curve, and zero lag. Those selling points also apply to Ram’s twin-blown “Hurricane” inline-six, that nevertheless still boasts the segment’s best numbers with up to 540 HP and 521 lb-ft. of twist.

Interestingly, it’s the 5.7 that General Motors is touting as having best in class towing, with a rating up to 13,700 lbs. vs. 9,700 for the 6.6. The smaller Small Block also boasts a higher payload, with a max rating of 2,170 lbs. to 1,510 for the 400-cube L78.

While these fresh bent-eights make a very compelling case for the fifth-generation Silverado/ sixth-gen Sierra in the mainstream, GM remains mum on finally taking the fight to the 6,000-pound dinosaurs in the room. As of now, the makers of the world’s most powerful V8s seem to have no intention of letting their new trucks stand toe-to-toe at the upper reaches of the domestic truck market where the Ford Raptor R’s Shelby-sourced supercharged 5.2L V8 makes 720 HP and the resurrected Hellcat in the Ram TRX now throws down a 777-horse gauntlet. Here’s hoping that GM has more up its sleeve for its trucks, but the all-new sixth-generation Small Blocks certainly look like a strong start!

Source:
General Motors

Related:
With the 2027 Silverado’s V8s revealed, the Corvette’s LS6 will be the only 6.7L V8 in the Lineup
GM Gearing Up to Produce New Sixth-Gen Small Block V8 For Trucks and SUVs
Chevy to Unveil New 405 Horsepower Small Block Crate Engine at SEMA

Subscribe Now: