Not a Small Block: C8 Corvette Z06 LT6 Shares Zero Parts With Its Predecessors

Outside of its familiar bore center sizing, the C8 Corvette Z06 LT6 is a totally new design, and perhaps the last.

We’ve discussed the brand new C8 Corvette Z06 LT6 V8 at length in recent weeks, mostly because it’s a massive departure from the types of engines we’re used to seeing power GM’s iconic sports car. The high-revving, flat-plane crank engine sounds like nothing else that’s ever powered a Corvette as well, not to mention the fact that it’s the most powerful naturally-aspirated production V8 in history. But it’s also worth noting that the C8 Corvette Z06 LT6 is a true clean-sheet design that doesn’t share a single part with any of its predecessors, as SAE International recently discovered.

This interesting tidbit was confirmed by GM chief engineer Jordan Lee, who explained that the only thing the LT6 shares in common with the automaker’s iconic small-block V8 is its bore size. “In today’s day and age, it’s hard to define an engine by one dimension [the 4.4-inch bore centers]. This is a unique engine on its own,” he said. That similarity is indeed significant, however, as every GM small-block engine built since its debut in 1955 also has 4.4-inch bore centers.

Regardless, the fact that nothing else present in the LT6 shares anything in common with any small block from history means that GM would prefer if we didn’t refer to it as such. For starters, the new engine features a dual-overhead-cam layout instead of the traditional overhead-valve setup, as well as a lofty 8,600 rpm redline and far-lighter internal components. In fact, the LT6’s forged-titanium connecting rods are 21% lighter than the titanium rods C7 Z06’s LS7 powerplant, while its forged-aluminum pistons are 8% lighter and the crankshaft is 33% lighter.

Interestingly, GM also went to great lengths to prevent the cooling issues that have plagued the C8 Z06’s predecessor, giving the new car a grand total of five radiators, revised side openings, and more powerful front fans. All of this adds up to a 50% increase in total cooling capacity compared to the standard Corvette Stingray with the Z51 performance package and enables the car to run at the race track in 100-degree temps with the air conditioning on.

The LT6 is indeed an impressive piece and an engineering feat, but it is still surprising to learn that it doesn’t share a single component with the many similar powerplants that preceded it. That alone makes it worth celebrating as perhaps the last clean-sheet-designed “small block” GM engine in history.

Photos: Chevrolet

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