After the GM embargo of 2025 Corvette ZR1 reviews was lifted one week ago, the whole enthusiast community witnessed the frenetic drop of 15+ YouTube videos, with enough turbo spooling and tire squealing to last the year. While many of us are a bit woozy after our ZR1 binges, much like feasting on that extra plate at Thanksgiving, countless enthusiasts may be left with the feeling: What else could we possibly see and learn about this remarkable 1,064 horsepower machine? Well, enter the enthusiastic and giddy car nut, Cleetus McFarland, whose propulsion to the top has been remarkable in and of itself. [Author’s Note: This article is FREE and not behind a paywall. Yes, FREE! If/when any pop-ups appear, please click to dismiss them and continue enjoying the article. One may require two steps–first, the arrow on the left, then the x on the top right.]
Cleetus McFarland, real name Garrett Mitchell, and his crew started pushing the limits of machines 15 years ago, and since then, he has slowly and methodically built his YouTube channel to nearly 4.4 million subscribers. More importantly, as it relates to the twin-turbo LT7, he became somewhat of a savant when he came to throwing turbos on anything with wheels. And as of late, Cleetus has now officially pulled off multiple races in NASCAR’s ARCA series.
Cleetus’s excitement was palpable during his review of the 2025 ZR1, but he was really like a kid in a candy store when he and GM engineer, Dustin Gardner, started digging into the new technological advancements, especially the twin turbos, of the LT7 engine. CorvSport has combed through Cleetus’s ZR1 review video, which has now surpassed a mind-blowing 1.7 million views, and will highlight the coolest tech from the new LT7.
What’s Inside Today’s CorvSport Tech Spotlight
- LT7 Technical Overview From Our Founder & Contributor, Scott Kolecki
- The Key Differences Between the C8 Z06’s LT6 And The ZR1’s LT7, From Scott Kolecki
- The Coolest LT7 TechToids & Images From Cleetus’s Review Video
- The Full Review Video From Cleetus McFarland
- Recent 2025 Corvette ZR1 Features From The CorvSport Archives
1) LT7 Technical Overview From Our Founder & Contributor, Scott Kolecki
| Type: | LT7 Twin-Turbocharged 5.5L DOHC VVT DI |
| Bore & stroke (in. / mm): | 4.104 x 3.150 / 104.25 x 80 |
| Block Material: | A319 cast aluminum with cast-in iron cylinder liners and four-bolt main bearing caps |
| Oiling System: | Seven-stage dry sump (8-qt. capacity) with oil-spray piston cooling |
| Oil Type: | Dexos R 5W50 synthetic |
| Cylinder Head Material: | A356 T6 cast aluminum |
| Combustion Chamber Volume: | 59.92cc |
| Compression Ratio: | 9.8:1 |
| Valvetrain: | Dual overhead camshafts (four valves per cylinder) with mechanical finger-follower valvetrain and dual-coil valve springs; dual-independent camshaft phasing |
| Valve Size (in. / mm): | 1.77 / 45 titanium (intake) & 1.37 / 35 sodium filled Nimonic (exhaust) |
| Fuel Delivery: | PDI (DI – Max pressure: 5,076 psi (35 Mpa / 350 bar) & Port Fuel Injection) |
| Firing Order: | 1-4-3-8-7-6-5-2 |
| Throttle Body: | Twin 65mm single bore (electronic) |
| Charging: | Twin 76 mono-scroll ported shroud ball bearing turbos (67mm MAR compressor), E-Waste gates |
| Charge Cooling: | Dual engine-mounted water to air charge coolers |
| ECU: | GM E68 (32-bit processing) |
| Horsepower (hp / kW): | 1,064 / 873 @ 7,000 rpm |
| Torque (lb.-ft. / Nm): | 828 / 1123 @ 6,000 rpm |
2) The Key Differences Between the C8 Z06’s LT6 And The ZR1’s LT7
From Scott Kolecki’s 2025 Corvette ZR1 Model Guide:
…But just how different is the LT7 from the LT6? To answer that question, we need to “drill into” the architectural nuances that separate the two platforms. Here are some of the key components that separate one from the other.
Unique to the 5.5L LT7 twin-turbo V8:
- Head castings with unique ports and a larger combustion chamber.
- Valve train timing and lift profile optimized for forced induction with higher exhaust temp enabling exhaust valves.
- A completely new intake system tuned for twin turbochargers.
- A CNC machined combustion chamber, exhaust and intake ports specific to the LT7.
- Dual, ported shroud, ball bearing, mono-scroll (76 mm) turbochargers integrated with the exhaust manifold to reduce the volume and distance from the exhaust valve to the turbine wheel for quick response with electronic wastegates.
- Intelligent anti-lag engine calibration techniques specifically for ZR1 that adapt and react to driving style.
The LT7 engine also builds upon this engine architecture with:
- Added block and head machining to support turbo cooling and oiling
- Counterweight changes to account for a unique piston, and unique connecting rod for the crank train
- A secondary port fuel injection system added to deliver the needed additional fuel to support the engine’s massive output
Of course, bolstering the engine output of the 2025 Corvette ZR1 also meant that the rest of the powertrain received the necessary upgrades to support and reliably transfer all that horsepower and torque to the road. To support the dramatic increase in output from the LT7 engine, engineers made numerous upgrades to the Corvette ZR1’s eight-speed dual-clutch transmission, including:
- Upgrades to the inner and outer input shaft assemblies.
- Increased gear capacity with strength increased via shot peening for all gears.
- Final drive refinements.
- Oil management to support increased vehicle longitudinal and lateral capability.
- Increased control valves to accommodate the higher required clutch clamp load for LT7.
Each LT7 engine is hand-assembled by the master engine builders at the Performance Build Center, part of the Corvette Assembly Plant located in Bowling Green, Kentucky… Continue Reading or Save For Later
3) The Coolest LT7 TechToids & Images From Cleetus’s Review Video
My favorite sentiment from Cleetus’s video was “If you think you’re just gonna throw a couple turbos on that LT6, not so quick…” As we noted, when Cleetus McFarland and GM engineer Dustin Gardner were together with the cutaway ZR1 and the LT7 parts strewn around the warehouse at the COTA compound, they were like kids in a candy store–you could literally see both of their faces light up when talking about this masterpiece.
About those turbos…
- Cleetus [at 8:50]: “Is this the biggest turbo on a production engine?”
- Gardner: “It is the biggest turbo on a production engine and we put two of them on it…”
- Gardner: “It’s a 76 mm mono scroll ported shroud on the compressor side, 67 MAR alloy wheel on the turbine side, and the whole Mani turbo end of this is a custom casting for this engine, for the ZR1, right, we wanted the turbo tucked up tight…”
Now, onto how this beast gets its oil…
- Cleetus [at 9:25]: “What the heck is this reservoir for Earl, gosh dang…”
- Gardner: “So there’s seven dry sump stages… so there’s four dedicated for each of the main bays, two handle the either head, front cover rear cavity, and the seventh is only to scavenge the turbos, cause the turbos are low and tight so they won’t drain on their own right so we actively scavenge the oil directly from the turbos…”
They say do something you love, and you never work another day in your life.
Let’s look at some internal differences between the LT7 and LT6…
- Gardner [at 10:17]: “This is my jam right here, dude, I could talk engines all day. So LT7, LT6… so the biggest thing you see in the wrist pin, dude, it’s a socket compared to the LT6. So the small end of the rod is really the only thing that’s different, and the (forged titanium) rod’s four and a half mm shorter. When we dish the piston and with the combustion pressures, so the top of the piston went down, and we had to make the piston thicker, we had to move the pin board down to make room for the heavier piston.”
Now, to the “Mani Turbo end”…
- Gardner [at 11:25]: “The whole Mani turbo end of this is a custom casting for this engine–for the ZR1, right? We wanted the turbo tucked up tight, turbine wheel, I mean, look, we’re only a few inches from the exhaust valve, so turbo lag energy right to the turbo, and with the MAR alloy wheel we can handle 1030C inlet gas temperatures, which is stupid hot. This is all one piece… this is all one cast piece… It’s a Borg turbo.”
How about those heads?!?
- Cleetus [at 12:02]: “What’s the difference in the head casting versus the Z06 LT6?”
- Gardner: “So the two biggest things are the combustion chamber side. The big thing is the volume up here in the widow’s peak, as we call it. So with the Z06, this will all be decked, as the head is. So combustion chamber volume there, but the biggest thing is on the exhaust ports. So, you see, it’s almost asymmetric, and these outer ports are turning inward and they’re all turning downward, right? We’re pointing it all to line up with this, so that the head is an extension of this manifold, and if you look at a Z06 one, these are evenly spaced and in it, they’re turning it up, right? Cause we’re going up into the equal length headers.”
4) The Full Review Video From Cleetus McFarland
Video Preview From Cleetus:
“Today we got to race on COTA with a BRAND NEW 2025 C8 Corvette ZR1. This puppy is 1,064 horsepower, twin turbo, and absolutely SCREAMS! What an opportunity, the car is amazing!”
Video Stats:
- Views: 1,716,351
- Likes: 87,000+
- Comments: 7,752
- Length: 35:57
Top Comments:
- “Chevrolet sent the right guy to explain the engines, i am LOVING his enthusiasm. You can literally see the sparkle in his eyes talking about his passion. Good job, great video. We love you cleeter!” @3BGamersHD
- “That dude had been waiting all day for someone to ask him about the engine in that much detail.” @ryanhoffmann9341
- “Love seeing the passion of that engineer. he’s a car guy 100%.” @blairski22
5) Recent 2025 Corvette ZR1 Features From The CorvSport Archives
- C8 Corvette ZR1 Battles Italian Supercars With 1,000 HP
- 2025 Chevrolet Corvette ZR1 Video Review Roundup
- Driving The 2025 Corvette ZR1 At COTA
- 2025 C8 Chevrolet Corvette ZR1 Model Guide
Thanks for joining CorvSport today! Are you psyched about this new ZR1 or what?!? Are you CORVETTE OBSESSED like we are? The team of renowned authors and contributors at CorvSport hopes you sense our passion for the iconic Corvette, and our vast database of articles and guides should prove it–5000+ features since Scott Kolecki founded CorvSport over 15 years ago! Join the fastest-growing Corvette community on our Facebook page, with over 169,000 followers (50,000 since January 2023!). Meet other hardcore enthusiasts and say hello. This is Douglas B. signing off–click here if you would like to view more of my features.
