GM 8.1L Allison Equipped Vs. LB7 6.6L Duramax.... FIGHT

Nick Priegnitz, CEO of Duramaxtuner / Calibrated Power, recently got a new truck in the shop. A gas GM 8.1L big block and well he wanted to put it up against our tuner Tim's DIY 'Til I Die LB7 to see exactly if the diesel is better than the 8.1L....
Nick goes for horsepower, fuel economy, and cost of mods to see where these two end up at. Take a look! Anything you'd like to see, drop a comment on this video.
Head over to duramaxtuner.com to check out our tuning! duramaxtuner.c...

[@DavidHerbers]

Those 8.1/Allison models bring stupid money now if in good shape. I remember during the surge in gas prices leading up to the crash in 2008, you could barely give those trucks away. 06 model years sat on dealers lots even with 30+% off MSRP.

[@nickpriegnitz5895]

Ironic considering the 06 8.1 is probably the holy grail of that configuration for anybody with their heart set on one of these rigs.

[@michaelbenoit248]

Probably because guys that know what Diesel maintenance costs guys are going for the gasser, & if they can get one with the Allison ofc it’s a good combo. Mostly because the Duramax has the Killer crank pin and when it fails the motor is 100% destroyed.

[@workingcountry1776]

3.50/ gallon gas and 10mpg empty. These are cheapest Silverados you can buy

[@KS-dg5zh]

​@@nickpriegnitz5895yes they have the 6spd allison with gave it smidge more gas mileage. There is a conversion kit available to make earlier allison a 6speed .valvebody and computer upgrade.i have a 02 2500hd with the 3.73 and 265 75 16 tires and have gotten 14 mpg average about 72 mph.go over that it dropped. I think it would pick up about 1.5 to 2 with a 6 spd

[@KS-dg5zh]

​@@nickpriegnitz5895 I forgot to mention the allison has the 6 spd hardware all ready in early models gm didn't want to have 2 overdrive at the time

[@mrpickle219]

I miss my 8.1 cab/chassis. Order it in November of 2000. It passed everything but a gas station. Loved it.

[@karlwahlfield6462]

same here lol thats so weird

[@Pharto_Stinkus]

I currently own 3 GM vehicles from this generation: A 2005 Suburban 2500HD (8.1), a 2002 Silverado 1500, and - the crown jewel - a 2004 Hummer H2 Luxury package. I bought the Suburban with 110k miles (it currently has 210k), the Silverado with 137k (it currently has 179k), and the Hummer with 53k (it currently has 79k). I daily drive all three, and have done many long-distance road trips and family outings in both the Suburban and the Hummer. I occasionally tow with all three (nothing very heavy), and have done a fair amount of light off-roading with the Suburban and the Hummer. I used to have a 2003 Suburban 1500. I gave it to my daughter with 275k miles on it. It currently has 300k miles, and she is still driving it. These four vehicles have proven to be the toughest, and most reliable vehicles I have ever owned by FAR, in my total 35-ish years of vehicle ownership. In the case of the Suburban's specifically, also the most versatile and useful. GM really knocked it out of the park in the early 2000's.

[@Duramaxtuner]

They really did. Thanks for sharing that, always love hearing these types of things.

[@justinblain1125]

Sorry to hear your vehicles are not to great. All combined they get 2 miles per gallon

[@Pharto_Stinkus]

@@justinblain1125 1st: Haterz gonna hate. 2nd: It's "too" not "to". 3rd: I never said they were the ONLY vehicles I own.

[@justinblain1125]

@Pharto_Stinkus yep your day is not good. Your a die hard chevy fan and it can be seen from a state away. Go ford and ram fck chevy

[@danielstump8772]

Keep going with the big block,Throw an exhaust,cold air intake and a throttle body on it. Those things were sweet trucks. Use an lb7 4 inch with a muffler and make a y pipe to hook into it. They sound pretty rowdy set that way.

[@nickpriegnitz5895]

I like where your heads at Daniel 👌

[@christophermix6845]

Definitely would like to see headers and a straight muffler. Even if the power gain isn't that high, the drivability would be completely different. Gas trucks are slugs with the crappy stock exhaust.

[@team_1j_jont-179]

Needs long tube headers for sure!!

[@joehenry9070]

I don't know how people can afford current diesel trucks for personal use. The truck prices are way too high. When the warranty expires the emission replacement or other components are very expensive. Rather, spend a little extra at the pump for gas or get an older diesel truck. Another great video Nick.

[@jacksonreid6412]

My LMM is about the newest truck I would buy. The newer ones scare the hell out of me

[@josephdemarco1469]

I just bought an LB7 because I thought I was going to have to move across the country for work. A Uhaul truck and trailer cost me $6500...this truck cost me $8k after I sold my old vehicle. its very good on diesel. 6-700km/ 450miles/tank with some mixed highway/city driving. whats hurting me is the outrageous cost of diesel in Canada, which is very new for us since diesel has always been less than a $1/liter and is not $1.65/liter. mine is pre-emissions so I never have to worry about that garbage.

[@TheElderOne2003]

I drive a 22 Ram 2500 6.7L CCLB as my DD. Honestly, about a wash on cost 6:40 older Ram 2500 6.4L Hemi. Yes, the oil change is a bit more, but I get around 10K per change, plus I do labs on the oil, each oil change with plenty of life left in it. Mpg is a bunch better in my new truck vs the old one DD & towing. Here is an extra cost ~$100 for fuel filters every 10K with the oil change. Granted, if something fails on a diesel like an injector, it does cost more, but the money saved on fuel, I'm not worried about it. Plus damn does my truck love to tow heavy loads like a champ!

[@StarHunter28]

I don't buy anything with Obama emissions. 07 and under for me

[@frenchonion4595]

Little extra at the pump 😂 Big blocks will drain your wallet as a daily

[@bobjohnson7797]

I have a 2003 GMC 8.1 Allison regular cab long bed with 65,000 original miles. That is a fun ride.

[@Duramaxtuner]

Love it!

[@brianp6965]

A few years back, I bought a 2001 Chevy 3500DRW with the 8.1/Allison. It has a Whipple supercharger/intercooler setup on it and 71k miles. I had no idea the timing was locked at 15 degrees. It's no wonder that even with the blower and 4.10 gears, that truck just doesn't feel fast. My stock LBZ feels like a monster by comparison. The Whipple kit is an early design with a piggy-back computer - they did not include a new tune for the PCM. They didn't even upgrade the fuel injectors! There are two giant injectors mounted in front of the throttle body that just blast fuel in front of the throttle plate under boost conditions. Watching this N/A truck totally wake up makes me realize, I've gotta get mine tuned. It'll probably run cooler too. 15 degrees under boost is ridiculous. I wish I was closer to your shop!

[@nickpriegnitz5895]

Your truck would be an ideal candidate for E85 and a real tune. You'd probably pick up 80HP or more all while improving engine efficiency across the board.

[@toddthezondalover645]

Running boost w a bad tune can turn into damage quickly. Good thing yours is low mile

[@Duramaxtuner]

Nick's got you in the comments!

[@waggtech4883]

My 05 8.1/Allison K3500 is a beast for towing a 15K 5th wheel. Gas mileage is always consistent. Having emerged from the diesel rabbit hole I couldn’t have been happier when I ran across this one from its previous single owner. It’s close to 290K with an unadulterated drive train. I’ve tried different tunes for both power and fuel mileage but am happiest with performance running the stock tune.

[@truckguyjoe]

I just spent a TON on a complete frame swap/frame off restoration of my 2001 HD Reg Cab. I just love the truck. Bought it new. I'll never get my money out of it, but that was not the point.

[@nickpriegnitz5895]

These are the next ‘square body’. You’re just ahead of the curve.

[@curtisstivason3695]

Enjoy your truck

[@JohnSmith-fp4ju]

I have a 2003 8.1L with the 6 speed manual. That thing is a blast to drive.

[@Duramaxtuner]

They are fun for sure!

[@natereinhold6180]

Ordered an 03 that way, but they said they discontinued the zf, so i had the allison. Was fun truck

[@323guzmandavalos]

I bought a 2001 gmc Yukon xl with the 8.1 and she’s still running strong

[@photomasterstudios9495]

Big block gas haulers are really cool with the absurdity of how simple and stout they are. Between the 7.4, 7.5, 6.8, 8.0, and the 8.1 they are really fun trucks that do what you need them to do and just chug along and have really good road manners in spite of their size.

[@TermiteBenny]

Time to take them to the truck pull this summer and see what they each do with a sled, or hook equal weight trailers and go on a real world road test and see how they perform

[@michaelbenoit248]

The Diesel would probably win except for EGTs cuz all they’re doing is more fueling that slowly kills diesels. More fuel means more heat, & needs more air or methanol to be cooler, or a turbo which means studs, & now it’s a whole ordeal to do it right.

[@TermiteBenny]

@@michaelbenoit248 I have no doubt the diesel would win, it would be fun to see how far apart they would be under real world conditions. On the dyno they were close so would like to see if that stays that way on the street or if the gap gets larger.

[@joshc5512]

This will be a good series Nick! Looking forward to more. Love both these motors and both have their place. Glad to see another diesel guy that likes the older big block gas motors too. 🤘

[@erickregnier1112]

I have the 2001 8.1/Allison extended cab long box with 270,000km and I love it

[@team_1j_jont-179]

That red 8100 is a gorgeous truck! I have an 02 lb7 pretty juiced up (turbo, tune, injectors, fbo) and i love every minute of driving it. Im usually all about aesthetics and my truck is dinged up and sun faded from florida but as soon as i test drove i knew it was coming home instantly lol.

[@WilliamGroves-f5t]

those 8.1s are good motors, only thing i really hated compared to all my diesels is you definitely feel the difference in torque. i dont honestly think you will ever get a gas motor that compares to a diesel when towing and working them

[@stephenmiller5023]

In 2001 I bought my 2500 Chevy Dually service truck with 11 foot utility bed & drove the snot outta it for company business. I can vouch for that 8-10 mpg first hand here . Was NOT cheap to fuel up each week , but I used to joke at how well it toted around almost 13,000 pounds of total weight on a daily basis & could probably rotate the world a couple feet if a hitch could somehow be attached behind it to the ground. In 2003 I bought my 2002 LB-7 2500 Crew cab GMC Sierra & with the diesel noticed an immediate gain in fuel efficiency, using that truck to haul around our 30 foot Toy- hauler trailer ( maxed out fully loaded at almost 14,000 pounds) of anywhere from 14 to 18 mpg after I made the usual intake & exhaust mods ( K&N filter in stock air box & 4” stainless steel exhaust down pipe back )along with a 6-gun tuner from Mr.Gale Banks . Unfortunately my service truck met an early demise in 2017 due to a pot head girl who blew through a stop sign at around 45 mph almost hitting me square in the left front wheel & sending me 18 feet sideways through an intersection ( by the Grace of God neither of us was seriously injured , but I sure wanted to injure her dumb ass), and that truck got totaled . We still own the ‘02 GMC, and watch your videos all the time Nick , and truly enjoyed this one here as it brought back some good memories of my “ White -Whale “ service truck . From Sunny So.Cal , THANKS !!😎👍

[@weegeemike]

I would LOVE to have an 8.1 truck. These 8.1/Allison trucks are UNICORNS. Ive literally NEVER seen one irl out in the wild. That big gasser would be perfect for my uses. I dont tow or haul super heavy often enough to justify a diesel. Most diesel guys never even get close to working it as hard or as often to justify the added updront cost of the diesel not to mention the expensive maintenance costs and (nowadays) DEF fluid and system maintenance and repairs. If i could find a clean 8.1 Allison truck id buy it IMMEDIATELY.

[@StarHunter28]

That's why you buy a pre emissions diesel, barely more expensive than a gasser to run

[@Duramaxtuner]

We get it.

[@user-je7gd9sr7o]

@@StarHunter28🤣🤣🤣 barely…I’ve never had to pull the cab or spend $10k on injectors or had to do a head gasket job.

[@jellyfrosh9102]

@@user-je7gd9sr7o It's a good thing injectors don't cost 10k then.

[@jonkobler1637]

RU near KC?

[@t.l.robinson2162]

I own an 8.1Yukon XL, an LBZ 3500 and a L5P dually. I love them all but I have the most fun with my 8.1!

[@jaredchilds8714]

Now let's compare a turbo version of the 8.1 to the Duramax which also obviously has a turbo. Expense may be a little bit closer at that point as will power output.

[@Bradygoodz]

They are gaining popularity. They are great trucks

[@danantes5223]

We bought new 2002 Chevy 2500hd duramax with 4 miles on it in 2001. I use it to pull out rv and running around. When it breaks it’s expensive, but we love it and will drive it until it totally can’t run any further.

[@darylmathis7125]

Nice Truck, & Good Teaser video! I'll be waiting for round 2 & more! GMT800 series truck's and SUVs are my favorite body style and drivetrains. I was looking for a used 8.1 2500hd ccsb about 10 years ago. There were few to choose from once you whittled out 6.0 gas & Duramax trucks. So after a year + of research and shopping around I bought my LBZ and haven't looked back! So much so, I'll be selling my 1984 Big block Blazer & Jeep Cj-7 to make room for another LBZ... or maybe... 8.1 if I can find the right one!

[@StarHunter28]

LBZs are amazing

[@timryan8174]

I currently own a 2001 2500HD with the 8.1L/Allison combo. Did a street tune a couple tests ago. No dyno. Gained approx 10mph on steep grades while towing my 24’ enclosed trailer with my Jeep and all of our gear in it. Noticeable improvement without the trailer as well. Love that engine! Not goods lie about mileage. It sucks. But I get the same mileage as many others I’ve owned while towing and have a ton more power.

[@rracerguy]

I had TBI 7.4L with 4L80E in 32' RV. only mod i did was take the tail pipe and exit it b4 the rear tire and it gain 5-10mph climbing hills Night and Day difference. I would bet if you did that you would pu another 5mph IMO

[@timryan8174]

@@rracerguy My exhaust is still bone stock. I do need to address that.

[@Duramaxtuner]

Thanks for the comment!

[@whitetailhunter7202]

I'm confused with the statement, "Expensive to operate diesel" ??? I own both a 04 1500 gas Silverado and a 05 2500 Duramax. Yearly cost to operate are nearly the same????

[@casey7091]

I’d like to see you throw a turbo on the big block 🎉

[@thelawnguy7373]

I have an ‘02 Silverado 8.1L crew cab with a 10” lift and 37’s. It’s not 4Wd but I sure has power. Love this truck. Bought it bone stock.

[@gregl2249]

You put a 10 inch lift on a 2 wheel drive?

[@thelawnguy7373]

@@gregl2249yea man, I know. I found a brand new lift kit for a really good deal so I figured WTH

[@gregl2249]

@@thelawnguy7373 Did anyone ever guess that it wasn't a 4 wheel drive?

[@thelawnguy7373]

Nope, unless you’re looking for the diff in the front you won’t know. People are surprised it’s 2wd when I tell them. I’ve never gotten stuck anywhere.

[@gregl2249]

@@thelawnguy7373how does it go in snow? I’d like to see a picture

[@kirkmason1527]

Good comparison! Toss a bigger throttle body on it and strap it back on the rollers

[@keelanarn2218]

Just for laughs I think it needs a little boost. Supercharger! Or a custom turbo kit with a stealth 64 for an lb7 and dyno test!

[@nickpriegnitz5895]

@wcfab are you listening?

[@keelanarn2218]

@nickpriegnitz5895 Does a gm 8.1L or an lb7 gain more power with a stealth 64? I think we all need to know! Lol might need pump, injectors, and E85 for that 8.1!

[@karlwahlfield6462]

i have one in a utilty truck, never tuned it but when the tranny went we did the massive cooler, higher stall convrter and shift kit and that really makes it tow nice!

[@NeffyWrenchin]

I remember riding in a an 8.1 01. That thing was awesome. Light then 35 in tires right up.

[@EchoTangoSuitcase]

I owned an 8.1L 3/4 ton Chevy and an LML 1-Ton. Pulled the same trailers with both. The 1-Ton was definitely the better truck for that work, though that was in large part due to the truck, not the engine. Still, as much as I liked the 8.1, it wasn't in the same league as the LML. Both got about the same mileage though.

[@ntsomelo7232]

After 100's x 1,000's of miles of gas and diesels.. the LB7 is still a soft spot as a work truck in my heart. If it was 2003 and we were pulling... not a chance. Only took ~10 yrs after that for Ford to copy it. Cummins eventually showed up. In any regard... gassers have a place, but for mileage and pulling for any length of time, no comparison.

[@Duramaxtuner]

Amen.

[@richardharvey8939]

I have 04 8.1 Alli combo with 4.56s a flat bed and all kryptonite front end goodies. 175k miles 2nd owner bought with 42k miles 10 plus years ago love it. Intake is the issue according to Raylar.

[@970sigrist6]

I have 296k on my 2002 8.1 with allison crew cab. Has some drips and marks the territory but I haul 2 atv with a rack and a 30ft camper with it. Not as roomy as my 2015 dmax was or as fast up hill. No Def, no bull crap exhaust emissions and nonextra costs have added up to more fun times. Besides for 13k you can get on of these with lower milage and they run forever.

[@StarHunter28]

That's what I love about my lbz, 400k miles, 17 mpg average, no emissions

[@tylervaughn6328]

For most people this is more truck than they will need! I’ve pulled my fifth wheel for years and have done nothing but maintenance to this truck, factory brake pads were finally replaced at 160,000. Owned a diesel truck for work got a little better mileage but I spent probably 12 thousand in five years for repairs. Can buy a lot of gas for that.

[@TurboTPI]

I love my 02 LB7 truck, and it feels very quick with your guys 5 position switch, but I also love big block gas trucks too! This is a great series to go on. Raylar(I believe is the name) makes some very bad ass parts for 8.1l engines. I still think the LB7 will edge out the 8.1l for heavy towing and sled pulling.

[@Duramaxtuner]

Thanks for the comment, we will check Raylar

[@jay_Jalapeno]

You do actually need the cam and intake for that power . A tune on average on these is only good for maybe 25hp and 30 to 40 foot pounds . You picked up almost double that because of the cam and intake . Mild flow job on the head , headers and a larger throttle body and you would have seen over 500 foot pounds at the crank

[@AximusPrime33]

Loved my 8.1. If they brought that motor back with an 8 speed and a 50 gallon gas tank. I'd buy one in a heart beat

[@shannonsisk]

This was a cool test. I always thought the 8.1 is super cool. Sometimes my duramax gets annoying with it’s complexity

[@jedpratte]

Love the old 8.1's. My dad purchased one brand new back in 2002 i think, still has it sitting in the shop with over 200k on it. Only ever had brake changes fluids and a crank sensor, otherwise its all original. Spent most its life pulling a 9,000lb camper all over the US.

[@Duramaxtuner]

Love it, thanks for sharing.

[@kevinlogan2306]

Having owned 4 duramax trucks I love 8.1's they are nutered from the factory they have a lot of potential although very little aftermarket support

[@kevinkalivoda3442]

The big name in performance parts for the 8.1 is Raylar. Pricy stuff but I think the only company making aluminum heads for the old 496

[@nickpriegnitz5895]

Yeah, I’d love to add a set of heads to this truck and I would have if they cost what regular aluminum big block Chevy heads cost, but the Raylar stuff is extra spicy

[@markrobedeau2223]

Have a 2002 2500hd with8..1 Allison combo.now has 445 thousand miles original motor just maintenance

[@shyecjj]

Owned 4 of these 8.1s , the 06 with Allison is a 6 speed double OD. Also own a 01 with a zf6 it was better fuel mileage and 10X more fun however it would eat clutchs. The other versions had 4l85e .

[@fastsilverado]

I have an '01 bone stock GMC 2500 with the 8.1 Allison. Hooked up a tug a war with a Ford 3500 dually with 7.3; I drug his ass. Love my 8.1. Mileage is 9 MPH whether with a loaded trailer or not.

[@Duramaxtuner]

Oh hell yeah!

[@zakswindle]

I do love the 8.1 but where I live 87 cost $3.25 and diesel is only $3.56 a gallon. Diesel and gas have been that close in parody for several years. That was one of the biggest reasons I sold my gas truck and bought a diesel. My LLY with tune gets 23 on the highway on 35s and my gas truck got 13 on the highway on 33s. Both of them toe fantastic but I prefer the power delivery of the diesel now that I’ve had one. Maybe a hot take but I would choose an eight point one before I got a 6.0.

[@Steven-gv1ke]

Yeah but when you factor in the additional $10,000 for the diesel upgrade, that's a LOT of extra gas you could buy. This doesn't include the extra money you save in oil changes and everything else as well. There have been many people documenting this very well and it takes basically over 10 years to recoup that additional cost of a diesel. Most people don't keep their trucks for over 10 years. There was even a fleet manager who made a video on this topic. He ran a 500 truck fleet. He had 250 gas and 250 diesel for 10 years. He has every last receipt for everything and after 10 years, went over all them. He ended up swapping the entire fleet to gas because it was cheaper. Now to be fair, their company wasn't towing 10,000 lb plus loads. They were mainly used as mechanic trucks with heavy tool boxes in bed along with heavy loads.

[@zakswindle]

@@Steven-gv1ke I know I left a lot of information out as to why I made my decision on a diesel. First off, I think the 6.0 gas trucks are your best bang for buck if you’re not on the upper limits. The 1500 HD and 2500 with that power plant is the best crossover of cost of maintenance reliability, power output and capability. I am explicitly talking about the 8.1 versus the Duramax. My 8.1 had an Allison transmission, when doing maintenance the only thing that was different was the price of the engine oil. Maintaining the transmission, the brakes, differentials and the transfer case the cost was essentially the same. I only got into trucks this big because the nature of my work. I do repairs on water, so I am pulling a workshop on a boat. Daily I was close to that 10,000 pound trailer weight. While towing the Duramax frequently got between 12 and 15 miles per gallon and the 8.1 frequently average 6 to 8 miles per gallon. For both of these trucks I bought them used and I got the 8.1 for $6800 and I got my Duramax for $7500. Trim wise the Duramax has leather electric seats and the center consul where the 8.1 had cloth mechanical seats and a jump seat. Both trucks are very capable and I will admit the 8.1 was substantially easier to work on. For me the diesel feels more natural and I personally like it. At this point, I have owned every engine combination you can get in a GMT 800. If you’re not towing at the limit or you do not just prefer the diesel I always recommend the 1500 HD or the 2500 6.0.

[@Duramaxtuner]

Totally understand.

[@shanebrown2963]

I had a 8.1 back in the day and that truck was a beast! I miss it every day. Only reason I got rid of it was the shit fuel milage for all the driving I was doing.

[@Duramaxtuner]

Such a fun truck!

[@jard1234567]

Insurance screwed me out of mine when I got into a minor crash. They totaled it when it wasn’t even that bad then gave me 7k when it had 120k on it and was in great condition.

[@blknblubkrdude]

I just sold my 2002 8.1L after years of 100% trouble free driving. $40 oil changes and nothing else. If they put one in a newer truck that was rated for my camper+trailer combo I would buy it with little hesitation.

[@bigmurph1447]

The 6.6l is rated to pull more than the 8.1l the 6.6 is more hp and tq that's the 6.6l gas

[@blknblubkrdude]

@bigmurph1447 GM dropped the ball with axle ratios on the new ones. I got to drive my coworkers '23 High Country pulling a 24' wake boat and although the 10spd is great the tall axle ratio just doesn't give the grunt an 8.1/6spd allison/4.10 gears does. At this current time, the Ford 7.3/10spd/4.30 gears is the go-to for gasoline. I ended up with a '21 drw L5P Denali because it literally cost less than an equivalent gas Ford 🤣

[@bigmurph1447]

@@blknblubkrdude tall gear ratio? It has 3.73. The duramax has 3.42. I have a 2024 with 6.6l gas and mine works great. I have pulled 18000lbs with it and it did very well.

[@jasondecker9196]

I went with the 8.1. Buying an older higher mileage truck, the ease of repair made my decision. 02 ccsb with 160k. Runs great. I want to tune it though.

[@Icutmetal]

@@bigmurph1447Apples and oranges, c’mon.

[@Jh46282]

I'm a diesel guy but will always love my big block gas more than most diesels. Still love the 6.0 tho, p0s but sounds like a plane

[@randysullivan5723]

Torque is what 8.1 and duramax are about but won't mentioned 🤷

[@CITYBORNDESERTBRED]

8.1 getting light again.. LT, Richard, now you.. let’s see a turbo build up head to head. Real world conditions.. towing, round town.. that’d be interesting. Awesome content, keep up the good work

[@nickpriegnitz5895]

I need to have LT build me a turbo setup like his. Nobody makes a kit...ugh.

[@Duramaxtuner]

👍 Thanks!

[@setunedouche]

Awesome comparison brother!!! Well done!!!!

[@Duramaxtuner]

Thanks for watching!

[@ImNotHereToArgueFacts]

I'm not sure why is horsepower the focus. Most people aren't operating in the rpm range where peak horsepower is calculated. I really like both of these engines. LB7 for heavy, consistent, long distance towing. 8.1L for weekend towing lighter stuff and daily driver. For those looking into performance mods for 8.1L, 8.8L heads are worth consideration along with a turbo or 2 (gap those rings accordingly). These even came in some Avalanch models.

[@fishinmagician3960]

I have an lly with your built trans with the 6 speed conversion and built trans tuning I’m just shy of 600 with some fueling and air upgrades and no adjustment To tuning. I was told 530 I pushed that with a weak CP3 and boost leak lol.

[@evanch123456]

I want some tunes for my 8.1!

[@cjespers]

Allison is making engines now? Cool!

[@matthewjensen9550]

That 8.1 is a clean truck!

[@Duramaxtuner]

Ain't she?

[@dylanbutler7804]

Would you guys be interested in seeing more power from the 8.1? I would for sure.

[@TheFarmersLife]

My dad had a single cab 2004 3500 with the 8.1. Got 9mpg empty and 9mpg with the gooseneck hooked up. 😂

[@Duramaxtuner]

Consistency!

[@michaelbenoit248]

Having owned 2 Diesels mostly the 95 7.3 and my current 1993 IDI a reason why I bought an IDI is because the engine is pretty naked. Mechanical injection, & no turbo. Makes a whopping 185hp with a 5spd behind it. Plenty of toque for me. As for the Duramax they are good engines. Better than the 6.0 BUT the injectors are abt 5-6k for a good set, and a fresh CP3. Also needs a FASS with it, studs, & they also have that crankshaft gear pin that’ll fail out of nowhere & trash ur $10k motor. Could also destroy ur injectors but mainly bends the valves. The fix is to weld the crankshaft gear to the crank so it can’t move or put a keyway instead of 1 pin.

[@Duramaxtuner]

Thanks for the comment! Appreciate you sharing your experience.

[@larrymolina7037]

You didn’t mention if you tuned out the torque management was reduced or taken out ? That makes quite a difference to how the engine runs also , you are correct on the induction side it starves for air .

[@nickpriegnitz5895]

Larry, you’re absolutely right. I left that out of the video but I should’ve put it in. I did adjust the torque management settings on the shifts which makes for a much more fun driving experience. 👌

[@larrymolina7037]

I think you should remove the torque management altogether or cut it down considerably. I own one of these and we removed alot of the torque management and the fuel economy went up by quite a bit plus it was alot more fun driving around town .

[@nickpriegnitz5895]

True story

[@bladenrexroth2555]

Opened up my 8.1 for a set of forged 6.385 rods and forged flat top Pistons with a 1.645 compression height. I put on a set of 8.8 heads with stiffer springs and a 8.8 intake. Makes 1 hp per cubic inch and torque is almost 700 ft#'s.

[@nickpriegnitz5895]

Love the idea of doing a higher compression version. Maybe my E85 plan would pan out better if I put a set of domed pistons and in it and ran 13.5:1

[@bladenrexroth2555]

@@nickpriegnitz5895 the 8.8 top end kit (heads and intake) alone helps with getting more fuel and air. The throttle body on the intake is much larger and feeds so much more fuel. A set of LS coils, a better fuel pump and a few other odds and end will get you that advertised HP/TQ figure to the wheels. Better Rods and Pistons will get you 1 hp per cubic inch. My Pistons are 0.005 below the deck which let's me use a thinner head gasket. I believe I'm only at 10.8:1 static compression. 13.5:1 would hurt the wallet at the pump. I run mine on E85 but it was a hassle to get it to be efficient. Had to replace the fuel lines, fuel pump and had to replace any part with rubber seal for stainless steel.

[@Duramaxtuner]

🤘

[@rizaptor7005]

Had a regular cab 2006 8.1 6 speed Allison. Was a monster to tow with. Would tow better than stock diesels of the day.

[@Duramaxtuner]

Nice!

[@IndependenceIron]

Would like to see the torque curve differences in the two trucks. Or rear wheel torque vs ground speed to get an idea of how well the two would tow since it is a Mustang Dyno. I have a mix of Ford V10 gassers, a 7.3 international, Cat 7.2 Freightliner and a 7.6 International all medium size F450 to international 4700s. The gassers are louder cause they rev higher to do the same work, but they still get the job done. I like the diesels and they do pull better, but its not by much. More depends on the gearing in the trans/rearend than the engine. For local trucks or occasional long hauls i would go gas if i could. Had to inframe our 7.6 due to a leaky liner seal. That was 10k dollars, which would have easily bought a reman 8.1 or two. But for consistent long haul highway use diesel is the way to go.

[@maisondillin9279]

Awesome video nick

[@Duramaxtuner]

Thanks!

[@Spinnaker617]

That GMC looked beautiful

[@Duramaxtuner]

Right!?

[@workingcountry1776]

Great truck for local work here in hills of NY. 10mpg empty vs 12 with 6.0 is kind of obvious choice. These are SLOW stock compared to 6.8L Ford in medium duty trucks I've driven for work back a while. The ferd had torque everywhere in rpm range and would merge w/ traffic w/ load about same effort as the 8.1 empty. I wonder if part was gm tuning....

[@Duramaxtuner]

For sure.

[@theSvrh]

Great video. I run the smaller 7.4 bbc and at the end of the day big block is always fun to run

[@Duramaxtuner]

She really is.

[@bartdaw6681]

That 8.1 is a nice looking truck!

[@brentmcmahon8188]

My 502 bbc runs great 36 degrees of timing and with Howard’s cams Edelbrock alum marine heads and to get me some more stainless water cooled headers with C&S Specialties 800 cfm holy airasol billet custom built car high dollar car but runs and starts just like a fuelie .

[@Mike-tb7li]

Did you know they put the 8.1 in the avalanche too

[@BurninGas8.1]

Cam intake and headers really wakes em up

[@nickpriegnitz5895]

Yeah, there's clearly more power on the table in the 8.1. We'll get there eventually. ;)

[@kennethfrancis6209]

2006 chevy 6.0 4l80e 268,720 🤌💪💯 8.4 mpg babbyyyy beastin shit daily

[@Duramaxtuner]

Hell yeah!

[@Steven-gv1ke]

I watched a video about 5 years back where a guy who was the fleet manager at a company that had 500 trucks, swapped half the fleet from diesel to gas. He ran this setup for 10 years and reviewed all the date. He had every receipt for every piece of maintenance and repair, and the conclusion was they were swapping the entire fleet to gas as it was cheaper. This is also when diesel was only about 10% to 12% more expensive than gas. Now diesel is about 33% more expensive which makes it even less cost effective. The only reason I see to ever run a diesel is if whatever you are towing is not within the specs of what the gas can tow and you MUST have the towing capacity of the diesel to safely do it.

[@StarHunter28]

I just like being able to go 250 miles between fill ups instead of 125. Out here in the desert you're likely to run out between pumps with range that low

[@Duramaxtuner]

Interesting, link us to that video if you ever find it.

[@rickymcu]

Cool vid. Wish we knew the torque numbers.

[@carlsmith9485]

Great video!! Let’s do a towing comparison.

[@brockgregory9166]

Great video! Awesome comparison

[@Duramaxtuner]

Glad you enjoyed it

[@bigmurph1447]

U need to do a 6.6l gas

[@fishinmagician3960]

You can watch the gas gauge go down with an 8.1 towing heavy in hill country lol

[@98durangopack]

Nice test buddy!

[@KS-dg5zh]

Richard Holdener dynoed a 8.1 with a manual throttle body and used holley management .it made over 400 hp and 550 ftpd of torque. Basically took away the torque management that gm has in the factory program.he also put a turbo on in and it made some crazy power and torque. Its on his you tube channel

[@northcountryredneck5979]

What’s the channel called I’m very interested to see that

[@nickpriegnitz5895]

I have watched Richard’s stuff. He does a really nice job with his 8.1 series. I can assure you the torque management was not an issue or holding the truck back in any way on the Dyno. The throttle was fully open, and all the time and fuel commands were as requested.

[@KS-dg5zh]

@@northcountryredneck5979 just type in his name in the search and it will come up.those dyno numbers are from when he had it on westech engine dyno

[@KS-dg5zh]

@@nickpriegnitz5895 i realize that but what I saw was when the torque management was off the 8.1 was a match to the duramax in torque. And everybody knows when these diesels get around 100,000 they turn into money pits.the 8.1s properly maintained go over 200,000 easily.

[@Duramaxtuner]

Thanks for the heads up!

[@taylorh3930]

Im still running a 1998 Z71 5.7 K1500 with custom cut high torque comp cam and full 3" dual exhaust no cat 87 octane

[@Duramaxtuner]

Nice.

[@TheHologr4m]

8.1 mpg as well.

[@77beast25]

Need torque numbers. HP is one thing even if the 8.1 was to put out more it will run out of torque way before the LB7.

[@nickpriegnitz5895]

Torque jumped about 60ftlbs with 87 and another 10 or so on 93. 355 stock to 405/415 (from memory). Might be off a smidge Because the gas engine makes its power higher in the roof range. It does not need 700 foot pounds of torque that the tuned diesel uses. It’s also a lot gentler on the transmission.

[@ScottHBrown]

I would open up the exhaust first.

[@robe3812]

I must have an odd ball 8.1, mine gets 16 mpg while towing my 20 ft boat.

[@Duramaxtuner]

You got the lucky golden 8.1

[@brentmcmahon8188]

But I do love your videos and I do have a 05 Dodge 3500 5.9 manual 4x4 and long bed dullay with 4door cab. This my second new Dodge diesel my first was a Dodge 2500 4x4 single cab long bed and the all mighty 5.9 12 valve and I loved that truck until I drove the 05 ride like a caddy and I pull a 35’ 5th wheel and I have a 10.6 Bigfoot truck camper the I pull my alum 200 hp jet boat and I pull a 22’ Donzi Classic 502 full roller but I have too many toys but Iam 69 and don’t want to sell my toys .

[@johncholmes643]

I've been a diesel engine builder, shop owner for 25 years and will not own a modern diesel.... I at one time I wouldn't own anything but a diesel. I own a 21 7.3 F350 that gets 9-17mpg and will tow and run with most new diesels.

[@Duramaxtuner]

Interesting!

[@breakinggames6356]

I am going to be using a rotted out suburban 8.1 but low mileage one as a donor for the my clean 4.3 ill be using the 8.1 and 4l80e/4l85e to replace the failing 4.3 in my truck soon how does the idea of a 496 SS sound to anyone also I have a duramax a zf6 with only 97k on it but the frame is going I gotta try to find a donor frame but both engines are pretty good

[@Mike-tb7li]

I miss my 02 chevy 8.1 crewcab dually 3500

[@jasonlovell3934]

GM should make a modern version of the 8.1. I think it would have a place in the market. They just need to add a 50+ gallon gas tank to them.

[@workingcountry1776]

Ford is using that 7.3L gas push rod engine in their big trucks. Theres videos with a hotshot truck with that engine. Colton Welding i think is the KZbin channel showing the 7.3L gas truck

[@BrandonLeech]

They put this engine/trans combo in the 3500HD for a couple years at the tail end of its production. That would’ve been a real workhorse rig around town. Hauling over the road long distance gasoline doesn’t work well for several reasons

[@Duramaxtuner]

Definitely.

[@djpratt7042]

What were the torque numbers?

[@nickpriegnitz5895]

Torque jumped about 60ftlbs with 87 and another 10 or so on 93. 355 stock to 405/415 (from memory). Might be off a smidge

[@gregbrammer336]

Try the comparison Lzo 3.0 305 hp 495 vs 8.1 340 hp Numbers close if get gears close maybe interesting

[@Duramaxtuner]

Now that's an interesting comparison. Thanks!

[@taylormoore8548]

Should build this truck and see what you can get out of it

[@ronkirkham3410]

I have had a bunch of 8.1 l trucks.I think they are great and you're right.Easy to work on super strong and reliable I have an 05 sierra That I'm trying to get back on the road.I would really love your input right now.I have a b******* tune and a raylar cam.So I know there's much more that I can do or should do so.Any input would be very greatly appreciated .

[@Duramaxtuner]

Hey, give us a call 815-568-7920

[@GreasyGorilla]

I’ve had one with turbo n another with nitrous. Great engine they took a lot of abuse.

[@Duramaxtuner]

Oh hell yeah!

[@farncoisbisson7737]

look up the c8 corvette build with a 8.1