Chevrolet LT6
5.5 L · V8 · naturally aspirated · petrol · 2023–present
Also known as: lt6, lt6 v8, 5.5 flat-plane, z06 c8 engine, gemini v8
General Motors' 5.5 flat-plane-crank V8 — the LT6 — in the C8 Corvette Z06.
⚑ It is unlike every other GM V8 in this catalogue. The others are pushrod cross-plane engines with two valves per cylinder; this is dual overhead camshafts, thirty-two valves, a flat-plane crankshaft and 8,600 rpm. Nothing about the LS or LT small-block families transfers to it — not the parts, not the service intervals, and not the diagnostic habits.
A flat-plane crank is inherently unbalanced in a V8, which is where its sound comes from and why it vibrates more than an owner stepping out of a LT2 expects. That is design, not fault.
It is dry-sumped and it is very new, so there is no settled long-term record and saying so is more useful than repeating early reports. What can be said is that oil grade, level and interval on an engine making this much power per litre are not routine advice.
The LT7 is its turbocharged relative and is refused as a designation in this catalogue's own tooling — GM used those three characters for a 1980s Buick diesel V6 as well.
Cars fitted with this engine
1 generation, across 1 make. From the authored catalogue — an absent car means the catalogue has not reached it, not that the engine was never fitted.
Chevrolet
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Posted about this engine
Be the first to write this up
Nothing posted about this yet. Whatever you found is worth writing down — even a dead end saves someone the same afternoon.
What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
Sign in or create an account to add what you found about LT6.