Here's Why the GM L8T is the Best LS/LT Engine

I think at this point it's no secret that the GM LS and LT are very popular engines, and for good reason. They're packaged very small thanks to their cam-in-block design, the OEM heads have incredible flow, a simple cam swap can pick up massive power, there are tons of different levels of displacement to choose from, and so much more.
For the longest time, the Gen III, Gen IV, and now the Gen V small block engines were available in only a handful of displacements, including 4.8L, 5.3L, 5.7L, 6.0L, 6.2L, and 7.0L. That is, until GM released the newest LT variant in 2020, with is the 6.6L variant, dubbed the L8T, which was designed as their new heavy-duty alternative to the 6.6L Duramax diesel engine.
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[@Dustrunnersauto]

If you guys enjoyed the video, please SMASH THAT LIKE BUTTON. It helps the channel out a huge amount and helps KZbin put the video in front of more people. Thanks for watching 😬

[@knockout4291]

Do 3.0 powerstroke next please 🙏

[@337speed]

This man’s engine knowledge 📈

[@Dustrunnersauto]

Now I just need to get my views like yours!

[@GregoryShtevensh]

Love your channel too

[@trentdawg2832]

337 you be Lacin folks up too bro!!!

[@TBCG]

Agreed!🔥🔥🔥

[@RageHP-RageHorsePower]

4 soon to be legends here

[@codyfarmer1]

This makes me feel so good about buying a silverado 2500 gasser. Gotta love a simple small block v8. No start stop, no hybrid bs. No fuel management bs. No cylinder turn off bs. Love this truck with this engine.

[@mrgmc6314]

The best thing about the 6.6 is no active fuel management bull shit ... no start stop ... no nannys... just a good engine...

[@cornelius6304]

Minus the lifters

[@mrgmc6314]

@@cornelius6304 have not had a issue yet ... hopefully not at all...

[@mrgmc6314]

@@cornelius6304 and the 6.6 is not known for this issue

[@Nobamaable]

That's a great engine, and I absolutely hate that cut out technology and start stop crap on most American trucks. I currently own a 2014 Tundra, because it was the only V8 I could buy that ran on all cylinders all the time and never cut off, but I'm considering the Chevy Custom 2500 HD so I can tow a bigger camper.

[@ryank4]

@@mrgmc6314 I just had to replace the cam and lifters on my 2020 3500hd with the 6.6 gas. 104k miles. they started making all kinds of noise, and the gm dealer said they have never seen it before. Extended warranty saved me $8k, and then a week later I had to replace the torque converter and tranny lines. Extended warranty for the win again. 2 months ago I was considering getting a refund for the warranty.

[@78heloman]

These gas engines are sort of the “Anti- diesel” as far as complexity goes. No AFM, Dod, start stop, and paired with a simple old 6l90, it’s the simple version, easy to live with, HD truck that anyone who’s fallen into hate with diesels will appreciate. Also, with the power this gas engine has the old “Gas or diesel” question is sort of different, almost like there’s a new middle option.Also, Dual alternators is an option.

[@larrycurci5453]

I love that dual alternators is a option. I also like how it's a "back to basics" engine eliminating start/stop, AFM, etc. Just let the engine run! Don't kill it by suffocating it like the diesels!

[@csh000]

Well it is the replacement for the L96, which is the flex-fuel version of the LY6. So yeah, I would expect it to be dead simple and reliable just like it's predecessor.

[@FOXRANGERTAILS]

I still love my 7.3Powerstroke and want a LBZ Dmax , but you are right the 6.6 and 7.3 Gas 2500-3500 are a very had argument now especially Off road and when you add a pro charger to the gas

[@HP-hm3pn]

I loved my Duramax, but got tired of emissions technology problems, so got rid of it and got a 22 Silverado 2500 with the 6.6 gas. I only haul moderately heavy loads so the truck is perfect. GM knocked it out of the park with this truck and engine.

[@DailyDriver.]

Thank god for no cylinder deactivation and no start stop. This things gonna be as reliable as the old 4.8 and 5.3 from the early 2000s. The Di might give carbon issues but still. This things got potential!

[@michaeljordan4571]

I don't understand why everyone is so hung up on DI. no one brings up DI being an issue when talking about the 5.9 Cummins, and that was the first time they tried DI. plus these engines don't come with EGR valves, which is the main culprit in the carbon problem.

[@nhlcfl7733]

I agree. To avoid future carbonized oil deposit build up behind the intake valves for example, one should consider an Oil Catch Can as I understand; I purchased one for my 6.6L (gasoline) and so far, over ~3000 miles driving, it's captured ~40 ml of oil. Otherwise, at ~15,000 miles on the odometer, my truck runs buttery smooth and the power band is very satisfying, even when pulling my 31 ft. trailer. PS, I can hear a muscle car roar when the engine is pushed / pedal is punched (nice!) that exists with this engine, but is sadly muted by the exhaust / catalytic system.

[@Back_door_bandit_98]

@@nhlcfl7733 It has that muscle car sound because it has that 10.8:1 compression GM knows how to build a solid gas engine with headers and no cats these 6.6 gassers would sound like a nascar.

[@god1st.530]

@@michaeljordan4571 I'm late but Thank you. I own 11 Gm 3-5th gens from ls to new Deactivation deal. And I've never had one problem. I still own 4 Gm truck, 2000 z71 stepside, 03 4.8, 2012 Gm z71 with Deactivation and a 2019 z71 . No problems. People take one flaw or lack of car truck engine care and blow it well over bord.

[@michaeljordan4571]

@@god1st.530 exactly, people don't understand that over time engineers refine these system, fix the bugs and make them more reliable.

[@ericvisser113]

Another big difference between the 6.2 and 6.6 is that the 6.2 recommended fuel is premium while the 6.6 is recommended to use 87 octane.. premium fuel costs more and allows for more aggressive timing which creates more power... Tradeoff is lower octane fuel and more displacement for similar peak power numbers.

[@jackdaniels2657]

Gm has a 6.6 lsx from like 2003 gas I remember it

[@larrycurci5453]

Less compression= less heat. Building the engine for working hard under load while maintaining safe temps.

[@nashvilleoutlaw]

The 6.6 is basically tuned to what the 6.2 would be if the compression was dropped to run 87. I like that Idea because the last 15 years that's how I've wanted to build my engines. Plan it to run like a hot street engine, then drop the compression to run 87. People in forums flame you for it but I'll gladly knock 20ish hp off a 500hp build just to run 87. 450+ is plenty of fun in a gbody toy/back updaily driver

[@Impala-qp9cb]

It’s meant to do work. Under load, these high compression gassers have had too high of compression for real work.

[@beekeeper6109]

@@nashvilleoutlaw , the compression ratio of the L8T is 10.8 to 1, almost a ratio higher than the LT5/LT4, which are 10.1 to 1 and 10.0 to 1, respectively. the control of the direct injection vs. port injection allows them to run the 87 vs. the high test. The high-pressure direct injection allows them to time the fuel to enter the compression stroke at the right time, eliminating the chance for detonation. No, some hate direct injection, and others love it; how the aftermarket deals with it, we will see.

[@JetTech1966]

I see a lot of comments concerning the DI in these engines, a JL catch can takes care of those worries for 150 bucks. I bought a 2022 Chevy 2500HD Custom model with this engine in it and absolutely love it. I installed a catch can on it when it was new and believe me, it catches quite a bit of oil, nothing beyond reasonable but I wouldn't want it in my intake. So I would highly recommend installing one. Aside from that, it is a joy to drive, dead silent on the highway. The 6 speed 6L90E is buttery smooth as well. I just love it.....tows our 8k lb camper with ease. My truck weighs over 2k lbs more then my buddy's 1500 with the 5.3L engine in it and we get the same gas mileage. I actually get better gas mileage when towing, we have the same campers.....kudos to GM....they hit a homerun with this engine transmission combo in my opinion.

[@slaytanic921]

Which can did you go with?

[@JetTech1966]

@@slaytanic921 J&L, used to be JLT. Amazon 150 bucks I think.

[@bobbyshaftoe]

400cu is the ultimate middle-heavyweight engine displacement... just as Poncho lovers :-)

[@jonathankipps9061]

A key thing you missed, is that the L8T is the only LT engine to come with a factory power steering pump. This tips the balance in its favor for classic repowers, since you would have to spend more for an aftermarket steering pump setup for any other LT engine.

[@jamesjones4309]

Totally agree

[@guysteel]

Good catch, very important. Thank you.

[@carguy3028]

I’m not familiar with the lt series engines but the gen 3 engines had a power steering pump, I would think the accessory drive from the gen 3 would bolt to the lt series. I’m sure someone has tried this.

[@jonathankipps9061]

@@carguy3028 There are some weird differences. For example, in order to bolt a gen3/gen4 water pump onto a gen5, you need to use an adapter plate. The water passages are just enough out of line with each other that this is necessary. GM didn't intend to reuse any of the front accessories when they switched to the gen5 engine, so they had no real incentive to make it backward compatible. There are companies that will sell you special accessory kits to allow you to bolt a power steering pump onto any gen5 5.3 or 6.2, but none of this was available from GM until the 6.6 showed up on the scene.

[@carguy3028]

@@jonathankipps9061 I had no idea, I put a gen 3 ls in my 72 GMC in 2010, I rebuilt it and it’s still running great. At the time I felt up to date, it’s amazing how fast you get behind the times. My cammed 6.0 makes good power and is reliable, since I don’t drive it very often it should last forever.

[@nhlcfl7733]

Loving my 6.6L L8T in my 2020 Chevy 2500 more and more after +2 years of ownership. Thanks for the detailed video; it is similar yet somewhat more in depth than the videos I watched KZbinrs interviewing the GM engineers for the engine and also their transmission back in late 2019. There is much +++ to write about my experience with my L8T and its mated 6 spd. transmission (more speeds does not always mean better fuel economy or durability; their 6L90 transmission was one of, if not their most reliable, and they even beefed it up further and used in their 5500 series for example). It has a “tall” overdrive top gear (6) for lower rpm highway cruising (i.e. ~1700). As mentioned, glad there is no Cylinder Deactivation or Start-Stop technologies (gimmicks as I've come to understand that will cause costly issues at a future time leading to $$$ repair, possibly wiping out the fuel savings altogether). My truck at +25,000km and +2 years ownership runs buttery smooth, and I am very happy with the power band even when pulling my +30 ft. trailer. Fuel mileage on the highway unloaded has been as good as 13.5 L/100km (17.5 usmpg) Hwy. during a nice 20C (68F) day with no wind, or average of ~14-15.5L/100km depending on conditions (as good as my 2002 1/2 ton).

[@Darthreloy]

Is your motor in a 2500 HD or what does it come in?

[@nhlcfl7733]

@@Darthreloy this engine is available for either the 2500 or 3500 series. Mine is a 2500. How was this helpful to know?

[@Darthreloy]

@@nhlcfl7733 Possibly. I will probably buy one from an engine recovery shop. Thanks.

[@chikisorozco4297]

@@nhlcfl7733 what year is your truck and also you said is a 2500 or 2500 hd ?

[@nhlcfl7733]

@@chikisorozco4297 my truck is a 2500 series , which in case one is not familiar with 2500 or 3500 series or when thinking of 250 and 350 (Ford), are “all” Heavy Duty trucks. Furthermore, “Super Duty” is simply a marketing term used by Ford for their heavy duty series trucks. What year is my truck? To help here again, this newly designed 6.6L has only been available in the HD lineup of Chevy and GMC trucks since 2020.

[@nonickerson]

Ive been looking at getting a new HD truck at first I wanted a cummins, however with the crack down on emmsion equipment deleteing up here in Canada ive decided to go gas plus its about 10,000$ cheaper. I was worried about this new 6.6 but after this video I think its safe to say my next truck will have the L8T.

[@aw11man26]

There were rumors and reports that GM was working on a new gas engine of over 8 liters but nothing concrete yet

[@27dmarshall]

I'd look at the 7.3L Godzilla. Better plus 10R140 10 spd, vs GM 6spd.

[@Back_door_bandit_98]

@@27dmarshall GMs 6L90 is better than the 10R140 it’s a proven transmission that does not see as much down time like ford has been seeing with their transmission’s. As far as the 7.3 being better that’s just an opinion at the end of the day the 6.6 has higher compression and more tune ability being direct injection.

[@aw11man26]

@@Back_door_bandit_98 I'm not a Ford guy, more GM for me, but so far the 7.3 seems like it's a beast of an engine. With a fully forged rotating assembly and iron block it is just begging for a blower. That lower compression lends itself well to boost

[@larrycurci5453]

2024 6.6L gas is said to have the Ally 10 speed transmission! 👍

[@timothybayliss6680]

This is the first gm block cast in iron with a 4.065 bore standard for a production piece. Some guys have already pushed it to 4.1 stroke and 4.185 bore. The L86 actually comes with the same heads and camshaft as lt1 engines, its the intake and exhaust manifolds and packaging with the programming that make the difference in power production. I didn't know the L8T had a forged crank with centre counterweight. Its beefy, its going to be fairly common.

[@craigmax3779]

Forgot to thank you for sharing your knowledge. Love your site

[@DeckofReason]

i have a 2021 with this engine ....we love it pulls 10,000 lb trailer with ease ....power is the best we have ever owned in a hd 2500 pickup..........

[@ryanthibeaux]

Have you owned a diesel?

[@Icutmetal]

That’s an empty statement without additional context.

[@brianbelliveau5551]

Pretty cool I just got a 2022 hope it does well and towing my camper trailer thanks bud for the update

[@rhishabdahal3025]

underrated channel

[@TheBarahona1]

I used to buy Toyota, and bought my first chevy 2006 4.8 love it and now I have a second chevy 2020 6.6 and I'm happy how much power this truck has.

[@derekdyer3929]

They finally got something right with this one.

[@anthonyvirgadamo898]

Got a 2024. Had a 6.2 loved it but needed more weight for pulling. Great info

[@kc2giw]

Swapped a mast L8t crate motor into my 65 Gto. Super happy with it.

[@texasconservativeveterans]

What did you use as an engine controller?

[@onegoodturngetsmostofthebl7499]

Purchased a 2021 Chevy 3500 HD with the 6.6L gasser and have thoroughly enjoyed the engine/transmission combination. For 2024 GM is allegedly doing away with the six speed in lieu of the ten speed tranny. The only downside I foresee is the direct injection over port injection setup. In addition, I’d like to see Chevy increase the horsepower to 475 and corresponding torque curve. Your analysis indicates the stock engine, heads, values, crank, cam, and guide rods are sufficiently robust to withstand incremental horsepower increases. So Chevy for 2024 let’s focus on wringing out some truly impressive performance figures from this engine variant.

[@safjistnipnog]

A truck I got to run for 35k miles was 2020 3/4 ton SWB and Quab Cab 4x4. Got 16 to 17 MPG not towing, towing a camper I got 8 MPG, It did drop to around 7 MPG in a lot of hills or high head wind. Still miss that truck.

[@chikisorozco4297]

Did you sold it or why did you got rid off it ?

[@Wilson_913]

For anyone wondering these are also an extremely simple swap for all 14-18 half ton trucks minimal wiring required. Re pinning some connectors and a tune and re using some accessories and it works. Id argue its cheaper to swap in a l8t in place of camming your l83 with long tubes just to achieve similar power.

[@robertglace813]

I have a 2002chev.with 8.1eng ,and gmc with 6liter eng, this new eng,sounds really good love to put in my gmc 2500hd thanks for your description

[@HardNorthOutdoors]

the LS7 wasn't pushed longer due to sleeve failure once modded. it needed to be re-sleeved but most just go to a bored over iron block for strength. so the 7.0 was dropped and the LS9 came to be as the powerful replacement with an impressive amount of engineering involved.

[@johnambro7181]

Opted this motor for my savana, can't wait for delivery.

[@brandonairey4040]

Perfect video. Thanks man.

[@justinsmith653]

A video on what makes this engine series so reliable, in both performance and work applications

[@guysteel]

Great video, subscribed

[@josephdunkle1152]

No AFM/DFM which is key to longevity.

[@bretmarstellar603]

Iron block adds durability for longer stroke and making power with lower octane (87) fuel.

[@pryme2013]

Good info but you didn’t mention this engine has a built in oil separator for the direct injection.

[@scottgas1299]

Odds are if you are shooting for 2000hp, you aren't using a factory production block or even heads for that matter.

[@aw11man26]

@Thomo5150 Bara used an iron block. Most LSs and LTs are aluminum. In the U.S. at least aftermarket blocks for these 2 engines are readily available as well as heads. For most big engine builders if they know from the start that they are shooting for 2000 hp they don't typically bother with factory castings. The LS/LT aftermarket is hundreds of times larger than the Bara. Not bashing the Bara, it's a badass engine. Reality is reality though. The Toyota 2JZ can make big number with factory blocks but even those start having issues in the 1600hp range, hence after market billet blocks

[@aw11man26]

@Thomo5150 being in Australia explains it. Truck LSs can be yanked out of junk yards here for a few hundred bucks. They are all over the place

[@bigadielldne7234]

Not 2000 stock u could push 3000

[@aw11man26]

​@bigadielldne7234 most people setting out to make that much hp are going to go with an after market block. With the money tied up to make 3000hp, and after market block isn't that expensive

[@bigadielldne7234]

@@aw11man26 that stock block can handle more hp then other engines w a aftermarket block.

[@PaytonDowns]

Could you do a video on the 392 hemi? Quality content btw!

[@kylevanwinkle2081]

Considering how detuned these engines are so they can be put into the 2b and 2c truck classes. If it ever made it's way to the 2a 1/2 ton class it would not be unsurprising to see 475hp and 500ftlb from it. While the 2b and 2c classes don't have fuel mileage standards they still have to meet EPA emissions which in a high work load environment you have to detune the motor.

[@shadowopsairman1583]

And can run on 87 Gas.

[@guysteel]

Not unsurprising ?

[@coreyoliver3653]

Another interesting note that I learned about ; after having investigated materials that, effectively, mitigate high-thermal loads : the L8T is equipped w/ exhaust valves made of Inconel. Provided that one is OCD, regarding heat management - he or she may want to look into this [ very, very expensive ] material. It’s purported to be “ that good ( and is used, extensively, in professional racing applications ). ” I’m attempting to build a bionic overlander - so ; I’m [ everywhere ], researching.

[@Re-InCarNation]

6.6L = 402 cubic-inch

[@mark8yes329]

The L8T nice addition of a drilled water passage between each cylinder, which the old 6 0 liter doesn't have. This is a big advantage over the LSX block, which means that the L8T will run cooler especially when using very hot burning propane. Propane burns ultra hot because it contains 37 percent hydrogen. Propane is also about half the pump price of diesel fuel.

[@Boostlee2023]

I have a gen v lt1 swap and 8l90 swap in my 2016 GMC Sierra, but I’m running the 6.6 crank and rods, and a set of mast forged 402 pistons, mast 402HO camshaft and lt2 intake manifold, full lt4 high pressure side fuel system and a hellcat in tank pump running e85, with a GM performance high stall converter. Mast sells this engine on their website as a 625hp setup and that’s tuned on 92 octane. My truck gets tuned in 3 weeks, but I’ve been on a basemap running very low timing 17* and rich at 12.5:1 at WOT and the thing hauls major ass as it is. So if anyone is looking for a beefy muscle setup, this is the one for you. I actually wish their were more people I could converse with that had similar setups, but seems like most people haven’t posted their setups like mine online yet.. please post away hahah

[@GMCJay_lly]

Commenting for support!

[@BuiltDifferent13]

Absolutely it's making me consider getting it. It might be the best LT engine now if GM would just give me a 4.8 L LT without DFM iron block, I would love them the rest of my life and mechanical fan mini HD engine but it only for base models

[@proto7688]

The intake port design is to make valve cleaning easier when direct injection causes a lot of hard deposits on valves.

[@ryannylander1819]

Appreciate your videos and was nice to see this one reviewed. This engine was on my short list for many of the reasons mentioned. Most notably because it lacked all the Fuel mgmt AFM, etc nonsense that plagues the other GM engines, well Ram’s HD 6.4 too. Durability is key and even though they may have given up a tad of durability using DI vs that of port inj like the newer Ford 7.3, it will allow a more precise burn at those higher hp levels later, with like you said the higher comp levels even at lower octane levels. However, since the next truck will sit a lot in my use case, won’t be going with a newer truck wasting more cash so really looking at the first gen Ford boss 6.2 engine in the SuperDuty lineup as a 12v replacement instead. So trying to learn as much as possible about the SuperDuty 6.2 engine iteration now! Got to see if you’ve done that engine review.

[@michaeljordan4571]

I don't understand why everyone is so hung up on DI. no one brings up DI being an issue when talking about the 5.9 Cummins, and that was the first time they tried DI. plus these engines don't come with EGR valves, which is the main culprit in the carbon problem. Also port Inj isn't all good, it's old technology so we are back to vacuum hoses and pumps that could leak and fail.

[@ryannylander1819]

@@michaeljordan4571 simple, DI normally has some additional maintenance down the road that’s not normally attributed to basic port inj. I think my 12v Cummins has had one leaky oring and that was the extent of my fuel issues on this truck over a long period of time. Some manufacturers have done a better implementation of DI than others. The 6.6 L8T, I’d still buy even with DI, given a different rear end option and maybe another 2 gear spread.

[@michaeljordan4571]

@@ryannylander1819 true but isn't the additional maintenance done like really done the line like at 400,000 miles. very few gas v8 ever see that number. and I haven't heard GM say anything about it needing additional maintenance because of the DI.

[@ryannylander1819]

@@michaeljordan4571 from what I’ve read over the years across forums and manufactures with DI engines, usually, 40k-100k there’s normally something to cleanup, carbon wise. Pumps, etc…. No perfect answer…100% depends. I don’t expect much injector or pump failure across DIs…. Just carbon related aspects.

[@michaeljordan4571]

@@ryannylander1819 oh you are talking about the sea foam carbon cleaners. I don't think they are too necessary. again these engines do not have egr valves and those were the main reason for the carbon problem. from the GM techs I talk to, the v8 don't really have carbon problems, AFM is a bigger problems. just makes sure you drive them on the highway for a long time every so often and you'll be fine.

[@jackass72]

After 20+ years with my employer, I finally got a brand new service van a few months ago, instead of run into the ground hand me downs: 2022 long wheelbase Savana 3500 with the L8T. I was pleasantly surprised to find that the 6.0L that was in my 2006 van had been replaced by this new engine that I didn't even know existed. Being a total gearhead, when I read up on the engine, I was impressed. Long story short, it pings and rattles like you wouldn't believe. Running 93 octane seemed to almost completely eliminate the detonation, but it was still there. Lately, doesn't seem to be helping much. Gas mileage is absolutely abysmal. Wouldn't be surprised if it's worse than the old van that has around 220K miles on it, with little to no maintenance and the check engine light was pretty much always on. Usually, the additional torque from the 6.6 is immediately noticeable, yet other times, it's a slug and seems like it's running very lean. My guess is that the factory ECM calibration is off, but it ain't my van, so whatever. Kinda disappointing.

[@Back_door_bandit_98]

I’ve honestly have had the complete opposite experience I’ve driven a bunch of 6.0 vortecs great engine my 2016 2500 had the last revision of the 6.0 it got the job done but felt like a total dog doing it. I got my 2020 3500 dually with the 6.6 gasser and it’s night and day not only is my MPG better by about 4-6 but the power delivery and get up and go it has compared to my old truck is crazy. My old truck with the 6.0 got 11.2-12.6 and that was going 65-75 on the highway in this new dually I can be going 70-80 and still get 14 mpg if I drop down to 65 it shoots up to 16 mpg pulling a trailer there’s no comparison this new 6.6 gasser is doing great for me I did notice a little bit of oil consumption but fixed it with changing my oil to Mobil 1 I was running Castrol both full synthetic but for some reason it likes the Mobil 1 better. You should check the engine oil maybe it’s a little low which is why you are getting that ping and rattle that’s what started happening to mine and I noticed it was about a quart low.

[@davidaylwin8710]

Yeah you have a bigger issue that hasn't shown itself yet. Engines run rich from factory 99 percent of the time. Rich is better than lean when something goes wrong. You are running bad gas possibly? 93 has alcohol it's better to run 0 percent alcohol 91 octane on all push rods.

[@BinkyTheToaster]

Hey, it's the "return" of the 400, sweet!

[@bucknasty69]

That’s what I’ve been saying! Now if only I could get a new Trans Am to put one in haha

[@wymple09]

I've never had an LT engine that wasn't a damn good piece of machinery. Everyone likes the LS stuff and that's fine, but I like the peace of mind that goes with the LT.

[@27dmarshall]

Good overview on L8T. Ford's 7.3L Godzilla (430hp/475 lb-ft) with 10 speed compares VERY well vs L8T (401hp/464 lb-ft) & 6 spd transmission.

[@huckwild6464]

Ah yes the 10 speed with known solenoid sticking issues that ford won’t recall. Amazing transmission if you want to keep it in park and never move it.

[@27dmarshall]

@huckwild6464 Mine is smooth, holds gears while towing heavy, down shifts at the right time to hold me back. Best automatic transmission I've owned. A lot of people love theirs.

[@huckwild6464]

@@27dmarshall I’ve went through 3 of them on 2020 f350 single cab xl used for hauling love the trans when it works but can’t get them past 100k they pull amazing until they don’t

[@huckwild6464]

Same for any trans though to be honest but 3 of them leaves a bad taste in the mouth at 7k a pop

[@matthewpeterson3329]

I was excitedly considering the 7.3 gasser until I found out about the head gasket issues due to the water jacket between the cylinders. A year ago, they got glowing reviews, but now that some folks have higher miles on the clock (say over 150k), they are having more failures and it is because there just isn't enough head gasket material between the cylinders. No doubt this new L8T will have issues here and there, but it is based on tried and true tech, so it has more of my trust from the jump.

[@kevin9c1]

The L8T being a heavier duty truck engine is also subject to more strenuous durability tests so that's another reason the power isn't as high as the 6.2.

[@markalford5406]

I bought this truck a 2021 gmc 2500 my worry is carbon build up on the intake valves. I didn’t know about this until I bought the truck. Hopefully the catch can I installed helps mitigate the problem.

[@mervynmontague1811]

Interesting and informative 🇯🇲

[@skycoh3581]

I'm really considering buying a 2500 Silverado with the L8T. Seems like a decent platform to have some fun with.

[@charlesmiller3134]

I have a 2024 2500 HD ordered.

[@thacuddypillzberry]

@@charlesmiller3134how long did it take? Or are you still waiting lol Ordered mine 12/14

[@bri-manhunter2654]

You can’t go wrong with any of the LS engines, especially the iron blocks!

[@chikisorozco4297]

This is a lt engine not ls engine .

[@Ws6Ms]

@@chikisorozco4297 it's actually based off the LS.... it not much different if you know anything about engines

[@02autogt]

Untill you start making serious power and then they can't retain head gaskets...

[@ajcates9136]

This just really changed the game

[@andyharman3022]

You haven't figured it out yet, have you? GM won't put aluminum block engines in their heavy-duty trucks. The iron block engines are meant to work harder. It's a duty-cycle thing. Don't talk about how the aluminum block engines are strong because they can be turbo'd to 1000 hp. With that much power in a light vehicle, 1000 hp is not reached but for only a few seconds. Hook up to an 18000-pound 5th-wheel and floor it up The Ike for 10 minutes, repeatedly, like RV hot-shotters do. That's where you need the iron block engine. Scoggin-Dickey turbo'd the L8T to 2000 hp.

[@theonlywazowski5366]

you should do a breakdown of all the LS and LT engines.

[@shadowopsairman1583]

Gen 3 SBC are LS, Gen 4 SBC are LS with Flex Fuel, DOD/AFM (VVT). Gen 5 SBC are LS Based LT with DI

[@Omega_TTRS]

There are stroked LT1’s in the 427 and 440ci range in the aftermarket.

[@CJColvin]

This engine would be a great swap for an old school muscle car or hotrod or even some Canadian Muscle cars like the Pontiac Parisienne, Acadian Canso, or the Beautiful Beaumont.

[@thomasm.7058]

Thanks, the "small block" engine is perhaps the best engine on the market, especially when cost and simplicity are considered. Fritz Indra was the executive director of advance engineering at General Motors Powertrain and said some years back, that the "Smal Block" cost $800 to build....

[@andyharman3022]

Yes. It's common knowledge in the industry that GM can build cam-in-block small blocks for a LOT less than Ford can build Coyote 5.0L's. Yes, the Coyote can make the same amount of power as the GM 6.2, but not for the same money.

[@beekeeper6109]

@@andyharman3022 , there are sleeved stock block/stock crank coyotes out there running 6.13 and winning drag and drive events on a 315 radial.

[@lorddoosworth8175]

@@andyharman3022 and the DOHC Coyote is much physically bigger than the pushrod LS/LT too

[@jwhmerica504]

I would love to see gm and ram bring back big blocks like ford did. That 7.3 is impressive.

[@chikisorozco4297]

I saw it on the news that Chevy is making a new engine that will be on trucks and it looks like is going to be pushrod 🙏

[@jwhmerica504]

@@chikisorozco4297 I hope so. I know they just came out with the 6.6 gas motor.

[@4alphazulu]

That 7.3 is impressive. The problem with the Godzilla seems to be with where ever they're getting their lifters. A lot of lifter failures showing up right around 30-35K miles.

[@jwhmerica504]

@@4alphazulu lifters seem to be a pretty common problem amongst many manufacturers lately.

[@4alphazulu]

@@jwhmerica504 yeah. That’s a fair assessment. It’s like whoever is supplying them is using crap metal.

[@robertworel5791]

I'm still awaiting the 7.4 direct inj ECT big block 4door

[@youraverageisuzuowner3699]

Can you do a video on the Toyota 1vd-ftv 4.5 twin turbo diesel

[@kook4u]

Boost certified from the factory ✅

[@Denali_Rebel]

GMs major flaw with the gas HDs is the gearing. On a work truck with the factory 31” tires the 3.73 gears work great. On a Denali with the 34.1” factory tires the 3.73 gears are less than ideal and mpg is absolute garbage.

[@XDrippingxXBlood]

why do people forget about wear resistance? the wear resistance on an iron block is much greater than that of aluminum.

[@jeffwolf8018]

What about the direct injection carbon buildup on the valves and intake? Is a oil separator needed for this?

[@Sas0Squatch]

I agree, show us a new big block

[@rickbaker9053]

Right... incorporate the technology of direct injection and variable valve timing and it'll be a lot closer to competing with some diesels

[@johnbehneman1546]

THANK YOU SO MUCH!!!! WELCOME TO THE FUTURE OF HOT RODDING!!!!

[@nickcautrell2514]

I'm sure people that get paid way more than me have already thought of it and tested it, my gut feeling is going to a smaller wrist pin while at the same time increasing the stroke seems like a bad idea.

[@larrycurci5453]

I would think it would piston oilers under the pistons for extra cooling.

[@jasonwilcox7322]

I am looking forward to using the new forged, center counter weighted 3.86 crank in a gen 4 build. Doing the math you can run an off the shelf piston (1.115 compression height) but combine it with a 6.2 rod and the overall height is only .004" less.

[@hughobrien4139]

I recently found a good deal on a bare L8T block. It had some handling damage to the deck surface. I was able to mill the block .015” and clear it up. I wanted to try and find an off the shelf piston already available. Mahle 930173225 is what I found. 4.125” bore with a 1.105” compression distance. Ordered a new GM crank shaft and got a set of 6.200” Molnar rods. Deck clearance came out to be +.004” out of the hole and I am fine with that. There are plenty of head gaskets available to accommodate. So if a person had a nice block that wasn’t hurt your figures would work out. I can’t speak to wether or not a 1.115” CD piston is a shelf piston at this moment but there is sure something out there for about any set up these days.

[@jovockwashington7732]

Can a lt4 supercharger fit on a L8t black and lt4 heads Also?

[@hughobrien4139]

Yes. They are one in the same. L8T blocks are not drilled for active fuel management on the lifters. You can even make an L8T block work for the base of a LS by machining the head dowel pin hole which is not a chore at all for any decent machine shop. The LT and LS block are basically the same. The LT heads have the intake and exhaust valve flipped so you have to use the correct pistons for the heads you are using.

[@AndreS_-df2nw]

@@hughobrien4139 what about cams?

[@hughobrien4139]

LS cams will fit in the block just fine. You could use the stock LS cam bearings in the L8T block however the rear cam bearing bore is notched for the fuel pump lobe and other fuel pump provisions. So I would opt for the LT cam bearings. The cam lobes will be reversed from LS -LT so that should be obvious. As far as which cam to go with? I wouldn’t make a recommendation without knowing exactly what many parameters are. I’ll say in short that if you’re drag racing a chassis car. Light weight no interior, then Texas Speed has some great cams to offer. If you’re running a full interior heavier vehicle hands down I’d suggest Gwatney Performance out of Arkansas. They have been putting in the work around that platform and have had some excellent results and have been improving on what they have learned throughout the entire time they’ve been working. They can be tough to reach over the phone so don’t get discouraged when they don’t answer or call back. They’re inundated with work. So be aware of that.

[@circuitkinggarage8643]

id love to swap my L83 5.3 in my 16 silverado with a L8T, I wonder if it'd be a pretty plug and play swap?

[@solvend]

People talk about adding oil catch cans to the pcv system. I figure if that helped it out they probably would have had it on there stock

[@donaldgminski8621]

Did they keep the same valve angle?

[@bongzonthebeat]

You should do 5.2 magnum! Ive had 3 go over 300k miles and all 3 still ran great and now have a single cab 96 dakota 5.2 5 speed with 234k and 99 durango 5.2 that i 5 speed manual swapped with 289k on it now the autos are bleh but NV3500 with 5.2 to me like a toyota pickup 5 speed. Just keeps rollin even bouncing off rev limiter

[@leepeterke4376]

The 318 has always been very durable

[@nosfedss]

Good video but I want to put this short lock in my 17’ 6 liter truck but I don’t want the direct injection crap on my truck so how can I do this? I mean the heads on the 6.0 are very different as you say the exhaust valves are swapped?

[@jamesyork6023]

Would have been REALLY awesome if GM offered a different ratio besides 3:73 for the 2020+ trucks. The 20-23 trucks with the 6L90e and 3:73’s felt similar stock for stock as a 11-19 L96 with a 6L90e and 4:10’s.

[@larrycurci5453]

Isn't it interesting that the newer engines are eliminating some of the technology for reliability? Hmm

[@robwhite3241]

I agree with you on that last part, the vortec 8100 needs to rise again! I think this engine is a good competitor to the 7.3 Godzilla engine but I think the 7.3 would gap it in a towing test.

[@6582rg]

No doubt about that.

[@shadowopsairman1583]

Erm Vortec 7400.

[@d-phoenix2198]

They could make a new Vortec 8200 using their 502 block which they have been selling for 20 something years. Just update the heads a bit and voilà.

[@geoffmooregm]

They already have a 7.4L LSX based industrial/marine motor. It's turnkey with 505hp and 515tq. Probably would need a little work and emissions tweaking for on-road applications but the proof of concept is there.

[@Back_door_bandit_98]

It would only gap it because GM uses 3:73 gears instead of 4:10 or 4:30 like ford. The 7.3 makes a little more hp and torque but the 6.6 peak hp comes in at 5200 rpm and torque at 4000 rpm while the 7.3 peak hp doesn’t come in till 5500 rpm and torque being the same at 4000 rpm the 6.6 also has better compression ratio 10.8:1 while the 7.3 is 10.5:1 so the 6.6 makes more power per liter.

[@DailyDriver.]

Great competition for the ford 7.3 Godzilla gas engine

[@tangyspongesauce]

This is like a new version of the Iron block L96.

[@josephp1592]

Lets hope its as reliable as the 6.0 it replaced, one of the most reliable v8s known to man

[@defaultname2333]

Is it a Compacted Graphite Iron block ?

[@Swagmoney696]

Does the l8t use the exact same intake manifold as the l86?

[@jamest.5001]

They. Should just throw in a 4" or 4.125" stroke crank, to get more displacement, and low end grunt,

[@jorgeguerra5876]

Always wondered why heavy duty gas trucks don’t come with turbos like the diesels do

[@jerryjessop6214]

Because diesels literally have to have a turbo to get enough power to do anything

[@johnandersonjjr]

Is it port injected too to avoid the dreaded carbon buildup?

[@williamhatch3332]

Do other 5th gen intakes fit the l8t

[@chadmiller6487]

How about reliability and longevity? As far as a fleet vehicle is concerned? Can we see this? 6.6 reaching 300k like the 6.0 vortec was capable of?

[@kirkdunn1379]

had 3 GM 2020 HD 2500s with 6.6 gas and 3 GM 5.3 1500s with 8 and 10 spd 2020 or newer and gas mileage overall isnt really much different........overall i was around 11mpg with 2500 and high 12s with the 5.3...........would love to get a lil more out of the 6.6 at some point....475/500 sounds bout perfect without putting too much strain and keeping reliability

[@cameronjodoin309]

I used to work at Uhaul and all their new Savanna vans have the L8T and we would do ridiculous burnouts on the offsite lot to kill time

[@kevinpazos9846]

My 2018 rcsb silverado is aching for one of these engines. 87 octane AND 401 hp? Yes please.

[@user-if3em9st7d]

Can I swap this engine onto my Yukon AT4 2023?

[@philllsxga.7737]

My Lt is tough!!

[@Iamthestig42069]

Quality control has been in a nosedive. The early 2000s ones are the best

[@jeli1347]

This engine looks and sounds great but direct injection from what I hear is problematic due to carbon buildup on intake valves. Why not just stick to port fuel injection? Any thoughts?

[@gen1c8rs88]

Just need's a oil/air separator catch can, just like a diesel. Direct fuel injection does not clean the oil from the EGR valve. Since the oil/air separator catch can has to be drained and the oil put back into the engine, OEMs don't include them for thier customers.

[@CanielDonrad]

Just have to use some of collection mechanism and clean regularly. Supposedly it's designed in a way to collect on its own. But a catch can is options. There are some self service options for intake cleaning that work quite well, check out stp intake cleaner. Clean 6-12 month interval and you may not even need a catch can.

[@DailyDriver.]

He mentioned it was due to the high compression ratio. It removes the risk of detonation that comes with using such a high compression ratio with such a low octane fuel

[@cholodude97]

About to hit 250k km on my 08 express 8lt

[@petersouthernboy6327]

The 8100 Vortec would have required some extensive design modernization

[@nicholasculp1294]

Was the 8.1 not a ps/lt base design?

[@stevenstrawn5009]

Left out the new 4.3 which is built the same it's a lt motor that puts out same numbers as the older 4.8 have both and still the v8 is just better hands down, but the new 4.3 has a sweet spot where it makes good power and torque.