Chevrolet Performance is now offering the naturally aspirated 6.6L V8 L8T as a new crate engine.
For those readers who may be unaware, the naturally aspirated 6.6L V8 L8T is the same powerplant cradled by gasoline-powered variants of the Chevy Silverado HD and GMC Sierra HD heavy duty pickups, and now, the L8T is the largest-displacement LT-family engine on offer from Chevrolet Performance. Peak output is rated at 401 horsepower at 5,200 rpm and 464 pound-feet of torque at 4,000 rpm, but unsurprisingly, the V8 also packs in loads of low-end torque along the way. Maximum recommended engine speed is 5,600 rpm.
In terms of construction, the L8T block is made from cast iron and incorporates six-bolt nodular main bearing caps, while the crankshaft is made from forged steel. The connecting rods are made from forged powder-metal, while the pistons are made from hypereutectic aluminum. Compression ratio is set at 10.8:1.
Further features include oil-spray cooling for the pistons and production-style exhaust manifolds. The L8T crate engine package also includes the throttle body, oil pan, PCV tube, evap tube, oil dipstick, oil fill tube, and cap, as well as a high-pressure direct-injection fuel pump pre-installed. However, it does not include the controller, harness, oxygen sensors, or Front End Accessory Drive system. Alternatively, customers can opt for the L8T Long Block option, which includes the direction injection cylinder heads, coil-on-plug ignition, oil pan, and dip stick, but does not include the intake manifold, throttle body, fuel pump, or fuel injectors.
In terms of transmission options, the 6.6L V8 L8T crate engine is available to connect to the SuperMatic 6L80-E six-speed automatic, with customers offered a few options for the torque converter, including a 2400 – 2800 stall, and a 3000 – 3400 stall. Further related parts and accessories include an accessory drive system, both with and without air conditioning, and the L8T controller kit required to run the L8T crate engine with the 6L80 automatic transmission.
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Comments
GM made a huge mistake by not upgrading the HP/TQ numbers for this engine, like Ford did with their HD engine lineup. I shake my head sometimes in bewilderment….
Definitely makes you wonder what they are thinking sometimes. They appear to be perfectly content being down on power. I’m anything but a Ford guy, but you got to give them credit for consistently giving their customers new and updated powertrain options. In addition to better HP/TQ numbers for the 6.6, I would love to see a modern version of the 8.1 make a comeback. With sky high diesel prices I think it would be a very appealing option. .
They may have fallen short on the numbers on paper but if you actually tow you’ll look at the low end numbers… and GM just increased their low end diesel numbers by 25%. While the GM trucks may not be rated on paper by their desperate manufacturer to tow 40k lbs like the Fords are, their low end numbers are what matters. Not to mention, the Allison transmission (that far surpasses its counterparts from Ford and FIAT CHRYSLER) is an absolute beast lol.
You do realize the Allison 10 speed is the same joint transmission that GM and Ford engineered together.
Only in gear production. The 10 speed has issues.
The 6L/90 MYD is the 6 speed. 1 1/4 longer pinion bigger gears stronger, my 2500 HD runs at 143° not towing.
the 10 spd in the cars and LD trucks have the GM / Ford transmission.
Its actually not but you can think that.
It’s where the torque falls that makes this engine. 40% more 2000 RPM torque than the old 6.0L. Perfect for towing. Which, after all is what it was designed for.
I agree with you 100%👍 only people who use trucks for what they are meant do (tough work) would know how tough and reliable 8.1 engines are! Its a shame GM doesnt make Big Blocks anymore! The good thing is that my fleet are only 8.1’s and 454’s. They don’t win many races but they do outlast all others in reliability especially diesels at least in my experience! It would be nice have the new GM trucks with Big Blocks again!
Just add the corvette intake for an Additional 20HP and 15tq. You’ll change your power band to being closer to deadline though. The thing to realize about the Godzilla upgrade is that Ford ran it stoicometrically mixed at WOT for fuel efficiency in dump trucks. All their doing now is running it a bit rich for more power. What this engine needs is actually more compression and a hotter cam as a performance engine, but if that was the case they wouldn’t offer it.
Here’s the reason for this crate engine. 6.6L IRON Block!!!! This thing is what you want, not the 6.2 when your going to add NOS and 35lbs boost. It’s got a durable bottom end and a lower compression ratio. Sure run it NA if you want, but most will boost this to high heavens.
Once you drive both of these engines in a truck you will understand exactly why that is. The ford may make more numbers on paper, but the power band has gaps and tends to be inconsistent feeling. The chevy has smooth torque all the way through. It is most noticeable when you have weight or are towing. I build busses on both platforms and the gm works much better for that application.
You are sooo” right!! 7.3 kicks it azz!!!!! To bad!! We will probably have to wait another 5 years till they get their act together to make a 454,7.2 that has what it’ll take! To bad,,,, I have the cash right now to buy a real engine like the Ford! Oh well ,,,,, I think I’m gonna put a Ford in my OBS Chevy!!!!!
Great engine ! ! ! How about dropping that in a COPO line of RWD regular cab short bed silverados , , , I know, see Dr. Ruth . . .
So they are going to sell this as a crate engine but won’t sell them in the vans even tho they’re available (just under constraint at this time). GM I hope you go bankrupt and don’t get bailed out again.
yah, well my 22 chevy van has this motor in it and it runs good
Your wright in regards with the hp/t # I’m sure that motor puts out more power than that. BESIDES YOU CAN’T TRUST FORD ON THAIR hp/t #thay put up wrong numbers in the past.
Guess you didn’t watch TFL do an Ike Gauntlet with a Silverado with the 6.6 gasser getting 11:53 and the Ford with the 7.3 Godzilla getting 8:42. Hell the 6.6 Duramax with the same trailer only did it in 8:24! I’m NOT impressed by GMs engines in real world towing!
The L8T needs a 10 speed transmission like the 7.3L Ford has. It will get the 10 speed Allison in 2024.
Ford still puts a 5.0 in their regular cab short bed RWD half ton ! [with stop\start “lame” tech], hey, I may sound like a broken record but this configuration is the heart beat of American hot rod. Ford Chevy or Dodge, those half tons rule. Hell Dodge will make a tradesman with a hemi if you want it! Come on Chevy ! ? ! ? ! ?
Did I miss he price in the article ?
Hmmm, L8T+68 Impala convertible = nice cruiser project.
Just the L8T block and crank are a great starting point. This engine has a lot more potential than the Ford 7.3L even if it is a bit smaller.
How so? The 7.3 is also a 6 bolt block with a forged steel crank.
The 7.3L does, but I am talking about potential. I think the 7.3L’s block (cylinder walls) and main bearing caps will prove to be rather thin. The L8T’s block is strong and heavy, very similar to the standard deck LSX block. The LT series also has a lot more aftermarket performance components available now, and will in the future. The 7.3L is a good stock truck engine, but likely will not be made in numbers anywhere near the LS/LT.
Dang, that’s a beauty!
Chevy, for some reason has always on the power of their vehicles, but they have more power than they advertise it or they make more power with a little bit of adjustment, and they’re better than ford or dodge they last longer
When they go bankrupt , Derick can go to Jap land and get a job , maybe South Korea? You can build Kias.
Kia’s are great cars. I own one and would buy another before Chevy. At lease Kia delivers on vehicles after you place your order (2 years waiting on 5 chevy’s that I’ve ordered, oh yeah I did try to support American automakers, bet you didn’t think that bud). This is another reason why America is in the toilets. Thanks for the tip Keith. See you in South Korea on the assembly line.
Where is this block made? Cuz I thought we had no more iron foundries in the US anymore…made in Mexico? & I’ve got 31 years in the very plant where the mighty small block Chevy has been made since it’s birth!
Why even release and engine like this for it to be so down on power? A standard 6.2 vortec has 420 hp out of the gate. And 430 hp in an rst Tahoe. Makes no sense to develope a weaker crate engine when the whole point behind a crate motor was better performance.
this motor was designed for commercial applications, designed for reliability and life at the cost of peak numbers. Dump trucks and cement mixers rare drag race or worry about 0-60 times. Go back a few years and compare numbers on engines like the 6.0 that were shared between personal and commercial vehicles, the same engine has a lot less HP and torque on the HD trucks. That said, these motors have a lot of potential for tuners in the aftermarket, so kudos to GM for making it available.
The GM and Ford transmission is in gear production only. They actually spin in different directions.
Gears are made in Cincinnati.
First of all Chevy always overbuilds the bottom end of their engines meaning you could easily I’m sure with the camshaft and a tune get probably 750 horsepower out of this engine and the bottom end will take it. On top of that they usually come out with an engine and then shortly thereafter or you’re down the road come out with basically the same engine but with free flowing heads, etc etc and way more power. From a business standpoint it’s a good way to do it because you’re not going to buy this engine if there’s one that’s way better with the same basic structure so they want to sell this one first. But like I said you can take this engine slightly modify it and shit all over 90% of Fords ever made.
And how much will the harness, ECU, trans controller, and front accessories set you back? GM is not very forthcoming with the details. Why?
Some people on here truly don’t understand what this engine is for. Posts saying peak numbers should be higher like Ford did.. this is a work engine, a pulling engine, peak numbers mean little, watch the area under the curve to see how the power is applied. You ever notice the new Ford and Gm and Dodge Diesels have a million hp and torque, but a real HD medium size engine, say a Cat C7 which is similar in size pushes around 50k lb rvs and FORD F650s and GM 6500.. with 300 to 350hp? Even ford and GM don’t use their own engines in real work trucks hauling real weight with all their power, thats because those lower hp and torque engines will work around a powerstroke or Duramax all day. This engine makes its power and more importantly torque all the way through the powerband, so you don’t have to turn 6k rpm to stay moving where the high hp engines make their power. Apples to apples people
Ok, Rexford L. Is clearly a Ford guy and was probably one of the people back in 2010 saying ‘pushrods suck, GM is stuck in the stone-age’ blah blah blah, the LS sucks, the 6.2L Triton is better, more modern, blah blah blah….before Ford went back to pushrods with their 7.3L…..becasue well….hmmm…..they are better for heavy work. He’s also the guy saying the 10 speed in the HDs is the co-built Ford/GM trans….wrong wrong wrong and more wrong. Rexford L….you need to stop posting now. Your embarrassing yourself.
6.6L L8T is a great engine, every bit as good as the 7.3L, and in a lot of cases better. It’s design is proven bullet-proof and it’s made with future growth in mind for the heavy-duty segment, and makes great power. Also if your in the Market for a great crate engine, it’s smaller, lighter, and probably a lot cheaper than the 7.3L. Also everyone know, they can make great power out of it with some mods…like stupid levels of power. Now in terms of the Trans everyone now knows it’s backed by the 10L1000 for 2024. For the Rex’s of the world, THIS IS NOT THE CO-DESIGNED FORD/GM TRANS. The 10L80 is that trans, and is designed for lighter duty 1/2 ton vehicles. The gear ratios are different, the case is different, everything is different. It was co-designed by Allison. With the 10 speed, that will make it competitive with the 7.3L for pulling. For those of you that care…I can’t beleive I’m gonna drop this comparison…that should make it comparable to the F350 up the Ike Gauntlet. I’m very interested to see what GM does with this engine in the future.
I had the original LS engine (98 Corvette) and yes it’s a great engine, but it’s a 27 year old design compared to the 3 year old 7.3. I realize you don’t think GMs $hit doesn’t stink, but all you have to do is look at the real world and the GM 6.6 Vortec isn’t that great of an engine.
I’m sorry but 500 lb/ft of torque and that’s stock. Add some aftermarket heads and cam and let builders start working it and this will be a mean package
The 7.3L engine was a clean sheet design that was started when Ford finaly understood their tall-deck 6.2L Triton wasnt as reliable, competitive, or as desired compared to other gasoline offerings in the HD market from the other brands. The new engine makes 430HP at 5500rpm and 475ft/lbs of torque at 4000 rpm, and it weighs 580lbs. It’s was introduced in mid way through 2019 and has started to have a decent following in the aftermarket world.
In response to this new engine GM created the 6.6L L8T. It is based on the new ‘LT’ platform that is the successor to the LS. It makes 401hp and 464ft/lbs of torque. It is less on paper but according to many sources makes more usable power, and has a better torque curve for towing. I don’t have personal experience with either of these engines so i cant say whether thats true or not.
From a powerplant design perspective the L8T is built on an extremely proven platform. The basic architecture has been around for over 25years and loved by engine builders everywhere. So, that being said, regardless of horsepower numbers, I think we all know by now which kid has already proven itself, and which one has to yet prove itself. The 7.3L seems like it will do well for Ford, but only time will tell. To compete with the L8T, you can’t just be powerful, you need to be everything else in the market also. The GM engine has already been there done that, from boats, to aircraft, to off-road to turbos, superchargers, dump-trucks, Corvettes, HD trucks, Purolator vans, drift cars, swap into anything 500hp,1000hp,2000hp,3000hp….the list goes on. Ford has ALOT of ground to cover to compete with that.
It’s a great engine, but why can’t they give us more Buick, Oldsmobile, or Pontiac crate engines? It would be nice if I could stop by a GM dealer and order a updated modern day version of the 400 Pontiac Ram Air 3, or a 455 Buick Stage 1. Why should we have to settle for the ordinary, run of the mill Chevy crate engines?
They call it the L8T because if you use a Chevy engine, you’ll probably be L8T to wherever you need to be.
I agree with you 100%👍 only people who use trucks for what they are meant do (tough work) would know how tough and reliable 8.1 engines are! Its a shame GM doesnt make Big Blocks anymore! The good thing is that my fleet are only 8.1’s and 454’s. They don’t win many races but they do outlast all others in reliability especially diesels at least in my experience! It would be nice have the new GM trucks with Big Blocks again!
The editor of this article state that the L8T engine has a low RPM torque peak. Nonsense. That’s not a low RPM . A high torque peak of 4000 RPM is now low RPM. Here’s the best example of a modern low RPM peak torque, it’s the Ford 5.4 liter truck engine, that had max torque at just 2500 RPM. How about the GM base engine 8.0 liter big block still under production, ( not the 8.1 liter ), has a max torque peak as used in heavy long 40 passenger school buses factory modified to run on propane or CNG. The torque peak is 2800 RPM and in some cases the development that GM contracted out to a Michigan shop, for the modern version of the 8.0 liter big block propane test used a a max torque peak of just 1800 RPM. The compression ratio was 10 to one. Max HP was just 2800 as developed in the shop running it on gasoline before it was sent to another company in Michigan for the propane development. GM sells the complete engine minus the intake manifold so the propane conversion shop adds their own intake and liquid propane fuel injectors. Here’s the direct link to the GM site for the 8.0 engine at the GM Powertrain site. https://poweredsolutions.gm.com/products/lfi-engine Notice is offered with a slight overbore of 4.27 inches instead of the normal 4.25 inch bore. It’s a high deck block so the old stroke of 4.25 stroke is can be increased to a high torque 4.75 inch stroke. Some of the GM aftermarket companies only offer a stroke of 4.5 inches when they modify the GM long block and they change the cam and add a different stroke crankshaft. Some of the industrial versions offered by these companies offer more than one version of the modern big block, by offering a bigger bore and longer stroke. Some of these companies also offer industrial versions of the 8.0 engine that to run on LPG propane or CNG, use a higher compression ratio or a turbocharger. By the way propane has a high 104 octane rating and CNG has the equivalent of 120 octane. Freightliner website has the details of the 8.0 liter school bus engine but it’s an 8.8 liter because it has a different crank. HP is rated at a low 225 but torque is higher at 510 foot pounds. No new diesel school buses are allowed in California for the past 8 years. Propane fuel contracts can lower the cost of fuel so it’s about 40 percent less than gasoline. There’s no carbon buildup when using propane of CNG. Propane is a dry fuel, so when the engine is first started the propane vapour doesn’t wash oil off the cylinder walls, like gasoline, so the propane allows about triple the life of wear on valve seats and cylinder walls and rings and bearings. A propane fueled engine minimum wear, makes it better than a diesel engine for long tern use. Yes, i said better, based on my 25 million miles ( 40 million kilometer ) fleet operation over a 25 year period of time. Your diesel comments are not valid because you don’t know a thing about running a commercial vehicle on propane. Diesel engines have serious problems with the carbon and the new cats that require cleaning of replacement after just 150,000 miles. Ignorance is bliss, i won’t respond to ignorant opinions comparing diesel to propane. Propane is the cleanest alternate fuel because it is 36 to 37 percent hydrogen and it’s found underground and doesn’t require a refining process, just a separation process in the oil field, where it’s pumped into rail cars, storage tanks or trucks for shipping directly to markets. Diesel fans, please reread this article.
Say what you want. When boosted this beast will eat Godzilla for breakfast.