GM's V8 Engines Are Reportedly About To Get Bigger

General Motors is getting ready to roll out the sixth generation (Gen VI) of its overhead-valve small-block V8, and early chatter suggests the new family will remain split into two sizes.

The two-tier strategy points to a smaller displacement V8 aimed at high-volume trucks and SUVs, and a larger unit positioned for performance models. GM already does this with the 5.3 and 6.2-liter versions of the current fifth-gen small-block V8. Officially, GM won’t say much beyond that a new small-block is coming and it's backed by an $888 million investment across several facilities. However, reports point toward 5.7 and 6.6-liter variants.

GM's next-gen small block V8s are expected to force the Gen V family of V8s into retirement—including the 5.3-liter L84, the 6.2-liter L87, the 6.6-liter L8T, the 6.2-liter LT2, and the supercharged 6.2-liter LT4.

Sources familiar with the planning claim the smaller displacement is aimed at mainstream half-tons like the Silverado 1500, with efficiency taking priority over performance. That fits with what GM president Mark Reuss said earlier this year about next-gen small-blocks being roughly six percent more efficient than today’s engines.

The 6.6-liter version seems destined for the fun stuff. A post circulating in Corvette Facebook groups—attributed to someone with internal access—claims the bigger V8 is likely to show up under the hatch of an upcoming Corvette Grand Sport, along with replacing the 6.2-liter OHV LT2 in the Stingray and the E-Ray. Speculation is being fed by recent sightings of wide-body Corvette dev mules with their engine bays sewn up tight to keep out prying eyes.

It's unclear at this point if GM plans to offer the larger displacement Gen VI small-block in both truck and performance flavors, similar to the L87 and LT2. With the Gen V engines, the difference is down to some changes within the rotating assembly and intake manifold design.

On the Corvette-specific front, it sounds like there won't be any changes to the Gemini DOHC small-block family, which is already, technically, a Gen VI engine. The Gemini family includes the Corvette Z06's naturally aspirated, flat-plane-crank LT6 and the ZR1's twin-turbo version of the same engine, the LT7.

Hopefully, the fistful of dollars GM is throwing at this project will clean up some of the longstanding issues truck owners with the L84 and L87 have been experiencing for the last couple of years. GM almost can't afford not to. Gen V engines equipped with Active Fuel Management (AFM) have experienced valve lifter failures, which can also cause the camshaft to fail. Meanwhile, the 6.2L L87 is currently under recall due to crankshaft bearing failures.

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