Vortec 8100: Everything You Want to Know

Old truck guys are very familiar with the good old Chevy big block. The Chevy C20 my father owns has a 454ci big block, and man can that thing pull. If towing is your main concern, then a diesel is probably your best option. But, what if you want a gas truck? That’s where the Vortec 8100 comes in.

Vortec 8.1: Engine Basics

The Vortec 8100 is rather obviously an 8.1L V8. It was designed as a diesel alternative in the GM pickup truck line-up. The Vortec 8100 borrowed much of its design from the 454ci big block we all know and love. The main difference between the 8100 and big blocks of old is the increased stroke. This is what increased the displacement to an impressive 8.1 liters.

You might be wondering, why isn’t this massive engine used in a performance application? The Chevy LS is super popular so why isn’t this engine? Well, there are quite a few things holding the Vortec 8100 back from ever becoming popular:

  1. Iron block and heads, total engine weight is over 750 lbs.
  2. Older big block parts don’t fit on the Vortec 8100.
  3. Chevy LS parts don’t fit on the Vortec 8100.
  4. Limited production makes them harder to find than an LS.

Vortec 8.1: Applications

Like I mentioned above, the Vortec 8100 was used in GM pickup trucks as a diesel alternative. But, it was also used in a few other applications:

  • Chevy Silverado/Sierra 2500HD & 3500HD
  • Chevy Suburban/Yukon XL 2500
  • Chevy Express 2500 & 3500
  • Chevy Avalanche 2500
  • Chevy Kodiak
  • Workhorse Class A motorhomes
  • T-98 Kombat armored vehicles
  • Malibu Boats
  • MasterCraft Boats

As you can see, the Vortec 8100 was used in a host of different vehicles. Chevrolet offered it in all of their heavy duty applications. The coolest application would have to be the T-98 Kombat armored vehicle.

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vortec1

Vortec 8.1: Performance Data

This part gets a little interesting. If the Vortec 8100 is supposed to be an alternative to the Duramax engine, then it must create lots of torque. Torque at low RPM is one of the single most important factors of a heavy-duty engine. So, how does the Vortec 8100 do? For this, we’ll look at the performance data for the GM truck applications.

Vortec 8.1:
330 horsepower @ 4,200 RPM
450 lb-ft @ 3,200 RPM

LB7 Duramax:
300 horsepower @ 3,100 RPM
520 lb-ft @ 1,800 RPM

I know what you might be thinking. “Why does an 8.1L only make 330 horsepower?” If this was a performance application that would be abysmal, however, this is a heavy duty application. It makes an impressive 450 lb-ft way down low in the RPM range. Other versions of the Vortec 8100 make as much as 550 horsepower and 690 lb-ft.

Vortec 8.1: Tuning Potential

The Vortec 8100 isn’t super impressive in stock trim, but it’s designed for heavy duty work. Like I said earlier, standard big block parts won’t fit on the Vortec 8100, so the performance parts available for it are close to none. However, this is one company who offers some very interesting Vortec 8100 parts.

Raylar Engineering is pretty much the only company interested in the Vortec 8100. They have developed multiple stroker kits to take it from 496ci to 511ci or all the way to 540ci. They also offer everything from camshafts to blowers. Their stage 3 package 540ci engine will make an insane 685 horsepower and 680 lb-ft of torque. Unfortunately, the stock Vortec internal components are fairly weak so any heavy modifications will require a forged bottom end.

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So, Raylar Engineering makes a bunch of really cool parts to wake your Vortec 8100 up, but is it worth it? If you’re just towing their towing camshaft and the 511 stroker kit will be a killer combo for you. If you want to go fast their bigger camshaft and 540 strokers will make big power for you.

Vortec 8.1 vs Duramax

Most of the trucks that are equipped with the Vortec 8.1 could’ve been equipped with a Duramax instead. Why would someone take a gas engine over a diesel in a heavy-duty truck? Although the Vortec 8.1 was designed to be an alternative to the Duramax, why would you want the gas engine? The main reason for this is diesel availability. Diesel isn’t available at every single fuel station, unlike gasoline.

As far as tuning potential it’s pretty obvious the diesel can and will make way more torque. You can easily get 800 lb-ft or more from a Duramax, good luck achieving that with a Vortec engine. Not only that, but the Duramax will also outlast the Vortec 8.1 engine. I’m not saying the Vortec engine isn’t a bad choice, but given the opportunity, I would always pick the diesel first.

Vortec 8.1 vs LS 6.0

Although we love LS engines, they aren’t exactly built for the same purpose as the Vortec 8.1. A 6.0 LS would make an excellent engine for a high horsepower street car, but not a truck that tows stuff a lot. The Vortec 8.1 was designed for maximum torque at a very low RPM. This is what allows it to tow much better. The 6.0L engine, however, is designed for more general use.

You could always supercharge or turbocharge a 6.0L to achieve the same torque as a Vortec 8.1. The only problem is the factory reliability won’t be there anymore. When introducing power adders the longevity of your engine is significantly compromised. I know people claim to have excellent reliability with modified engines, but there’s a reason why manufacturers don’t push engines that hard from the factory.

The manufacturers thoroughly test their engines for longevity and reliability. Once power is increased, long term reliability is decreased. Hence why the Vortec 8.1 can reliably achieve a much higher torque number than a 6.0 LS.

Summary

So, the Vortec is an excellent heavy duty engine. It nearly matches its diesel brother in torque and beats it in horsepower. But, due to its heavy weight, it is rarely swapped into hot rods. It is slowly becoming more popular thanks to companies like Raylar Engineering who can turn it into an absolute monster. Let me know what you think of the Vortec 8100 in the comments below!

About Bryce Cleveland 276 Articles
Bryce founded Dust Runners Automotive Journal in 2014 as a way to write about the cars he found interesting. When he's not writing for Dust Runners he's writing for Power Automedia as a freelancer. He currently drives a 2015 Fiesta ST and absolutely loves it.

42 Comments

  1. I just discovered this monster exists! The problem is engine management. MSD doesn’t make a box like they do for the LS cousins. Anyone who has information on something like that please let me know!!

    • the 8.1 is a 24x reluctor crank trigger and a phase cam sensor just as an ls1 they use the same computers and ls ignitions can and do run 8100

      • You can use a msd box meant for the other ls engines and it should work. When I was doing a setup with this engine I was looking at using the msd 6014.

    • I just saw this article and thought I could offer a different perspective. I had a 8.1 in both my Avalanche and my 23.’ Essex boat. The Mercruiser 8.1 was factory rated at 425 horsepower in the version I owned. In both cases the 8.1 s were among the best engines I have ever owned. I towed many thousand miles in Duramax 2500 Silverado over the same route as I did with the 8.1. The 8.1 did get lower fuel mileage than the Duramax : 8 vs 10 mpg with a 24’ enclosed trailer being towed. I had made the same trip over 20 times with both engines. The Duramax really performed better above 5,000 feet due to the turbocharger. On flat ground there was little perceived difference in power. In the boat the 8.1 has lasted over 15 years and 750 hours without anything other than normal yearly oil changes. The increased maintenance costs of the Duramax negated the better mileage . The 8.1 is a great engine.

  2. Nice article to read but I will have to disagree on the longevity of the Duramax vs.the 8.1 I’ve worked on multiple Duramax and 8.1s and have talked to many who agree that the 8.1 out last the 6.6 Duramax almost every time in respect of dollar signs and total break downs. Many of whom I’ve talked with that have 8.1s myself included having 3 the 8.1 asking as it’s maintained some what well will last 300,000 plus with very little problems where you can garrenty with a lb7 you’ll be dumping thousands into it. Yes a select few have had great luck with the lb7 and haven’t had to put much money into their Duramax but me personally being a mechanic and mainly focused on gm over all I can say hands down a 8.1 will last just as long if not longer than a lb7. I personally never thought the 8.1 would amaze me pulling but wow was I wrong. Call me stupid I don’t mind but when pulling our dozer my 2002 stock 8.1 will tow just as well as my bosses 6.4 powerstroke. Long story short I like your article I love the 8.1 and wish they were still on the market today from gm

    • Yeah, I chose the 8.1L to have the towing power without the high dollar maintenance of the diesel. I’ve had cummins and powerstroke and I have 3 cousins with the duramax but the repairs are so costly with a diesel.

  3. I agree, the 8.1 is a workhorse and as reliable or more than reliable than a Duromax. I have seen more folks interested in the 8100 for drag applications. One thing Rayler offers is aluminum uppers to reduce the weight, but there’s something to be said about a cast iron block – without it, you’d be on two wheels. I’ve towed as much with my 8.1L as I have in our 01′ F350 with the 7.3L, and also our 2013 6.6L Duramax. Yes, in the low end the diesels may have an easier initial roll, but at 283,000 miles, the 8.1L still has no problem rolling a 30′, 10-ton tandem axle gooseneck loaded with seven bundles of crossties. I actually prefer the 8.1L with the Allison over the 7.3L – a much smoother pull. Way over the legal limit, but it hauled it just fine on the interstate. Stock motor with normal maintenance – the only things replaced attached to the motor have been a crank sensor, pully tensioner, and alternator. I’m beginning to look for an engine shop for an overhaul at the 300,000 mark. The 8.1L is a big motor, big fuel consumption, and big sound – seems like a perfect combination for a hot rod. Bigger is better, right?

  4. Overhauled a 97 1500 suburban 4×4 with the #vortec8100. She eats everything alive on the highway and tows 10 like a snap. Please call Jeff @ Harris Used Truck Parts. They have engines galore and will put any #Duraburb to shame. I am so happy my wife is jealous!

  5. I own a 2001 chevy surburban 3/4ton with the 8.1 Litre engineI tow my camping trailer that weighs 7300lbs dry.This vehicle tows it with ease.

  6. I had a F350 7.3 and it could hardly pull it’s self around so I replaced it with my 2003 HD 2500 GMC. The GMC has been great and now has about 145K on it so was looking into a replacement engine. After reading about these engines running up to 300K maybe I still have some life in the old mill. The 8.1 has only had mobil 1 oil in it, has 4.10 gears and the allison 5 speed trans. I mainly pull a 10K horse trailer and you really know it is back there. Someone said they were getting 16 mpg but didn’t say if that was an improvement or what they got before? My 8.1 seems locked into 10 mpg at best. I would like some more get up and go and if better mileage were possible that would be great. maybe do the intake and put a performance tune on it?

    • Go to youtube and watch Hptuners 101, beginners guide – GM ECM tuning overview. It’ll give you an idea of what GM left on the table

    • Hi Ken I might be late with an answer for you but here’s what I did. I got it tuned with HP tuners, the ecu on most new GM vehicles are tuneable through HPtuners and EFI live, that means if you find a good tuner in your area they can definitely improve the performance of your 8.1. I did my own tweaking along with my transmission through HPtuners. The best economy I’ve gotten was 14mpg unloaded I don’t know if that helps. I’m still modifying my Suburban but next for me is a rebuilt trans and shift kit along with a Hughes towing Torque convertor I’m hoping that it’ll hold gear longer and lower

  7. I’m Looking To Tow A 30′ 3 Axle Toyhauler. Has Anyone Looked Into Using Propano Gas ? Would This Be Cost Effective?

  8. I can’t say enough about the 8.1. I’ve owned dually’s that my 2000 2500hd has put to shame. Actually all the other trucks I broke with a 20′ flatbed trailer and the weight put on it. I’ve had the 2500 for about 4 years now and I love it. Only thing is torque management. Can’t I just pull a wire and add a required voltage to remain constant? Too easy,I know. But theirs got to be an easy way around it.

    • You can get HPTUNERS or EFI live and tune or adjust the trans and engine to what you need. You can also fine a tuner in your area to make the adjustments for you. The factory GM ecu on almost everything after 97 are able to be accessed and reprogramed

  9. Go to a salvage yard and get a complete donner engine combination from a 2001 to 2006 2500. pick up every nut and bolt you take of. every thing, hoses , cooler lines, computer is interchangeable. I prefer the 4l80 trans as it requires less HP to turn it. Also all the programming is in the computer. Very easy.
    LH

  10. I drive a 2001 suburban with the 8.1 in it. Love the engine to death even being a deisel freak. I’m a welder so towing all the equipment and machines can get heavy, I do own 2 duramaxs but I drive suburban daily. The 8.1 will tow absolutely anything I put behind it no problem. I was towing 12,000 up a mountain and I forgot I had a trailer that’s how amazing the truck tows. Now gas on the 8.1 is a little crazy. I get 6 MPG and it’s a 40 gallon tank so it’s not cheap to fill up. I’m a die hard Chevy fan and always will be. I’m going to keep that 8.1 forever. Not the biggest gas heavy duty fan as I own 2 duramaxs with one of them being a dually, but by far the 8.1 is THE BEST engine I have ever had in my trucks. Highly recommend

  11. I have a 8.1 in my 04 Silverado single cab I use it for everything 2 wd when people c it they want to buy it I use it for everything but she not Towing anything I use it as a regular car on hwy 12 not bad runs great

  12. I have owned a 2001 2500HD Crew Cab 4X4 with the 8.1/Allison combination since early 2010. The only work to the engine other than spark plugs and wires that I’ve done is replace the fuel pressure regulator, which is a cinch to get to on this engine. They put it in such an easy place that I was sure the engineers knew that it would need replaced one day and wanted to make it easy to do.

    The biggest problem with the truck has not been the engine. Mine has about 150,000 miles on it. All it’s ever done is pull trailers. It doesn’t use oil. It doesn’t rattle. It doesn’t knock. It’s perfect. The biggest problem with this truck has been all the damned rust! The body will rust away before the engine dies. Other than that, the transmission range selector switch on the side of the Allison has given me a couple of fits, but it’s a simple enough change, even if the price has more than doubled for the part in the time since I bought the truck.

    I get 10 to 12 miles per gallon empty or loaded. I just cannot eke anything more out of it. This truck isn’t meant to be a daily driver. It’s a truck meant to work. My daily driver is a half-ton that gets 18MPG.

    The 8.1 pulls like no other big block that I’ve ever owned. Only the Ford 460 has come close, but even then, my 8.1 is stronger than the stock 460 that I once drove. My 8.1 is the most reliable engine that I’ve ever owned. It’s too bad that I cannot say the same about the rest of the rusty truck.

  13. well I just got a 2001 8.1L and all the goodies to drop it into my 1978 chevy mud truck. 6″ lift, 40″ hawgs, detroits, snorkel and many more… cant wait to see how it performs vs my 1991 caprice police motor (96 Tahoe heads, comp cams xtreme 4×4 cam, holley truck avenger)

  14. I have a 2000GMC8.1 not to long ago i let my grilfrend drive it she put desil in the tank took off then it blowed the oil plug out.I cleaned the desial out put gas in it then she fired up took off not 1 mile later she started knocking i shut it down got to the house with her fount the problem new oil plug new oil but still has a knock what do i do

  15. I am on my third 8.1 and they have all been rock solid. I had a 2003 Suburban 2500 that I bought brand new (never should have sold that truck), a 2001 2500HD and my current truck is a 2006 2500HD with the 6-spd Allison and 4.10 gears. It is a beast and will roast the rear tires off the line. The fuel economy sucks, about 10 mpg, but I didn’t buy this truck for the economy. I need it to pull my 26′ boat and 24′ camper. I had a 6.0 in a 2006 2500HD with the 4.10 gears and there isn’t a comparison. The fuel economy with the 6.0 was about 12 mpg, not much better.

  16. I acquired a avalanche 2500 earlier in the summer and my only complaint is fuel consumption. Had 175000 miles and drives like a dream has 3.73 gears with 35″ tired that I thought might be a little higher than acceptable. But with the programmer providing ability to re-tune the tranny I’m pleased to say with this setup I have only a couple times averaged 15 mpg, 12-14 hwy. Although city and towing has more reduced economy 8-10 city and 8-11 hwy towing, don’t tow much, have a 87 one ton to do most that with. With all the aftermarket wheels lift and chrome added I’m more than pleased with a 8,000+-lb truck that feels as nimble as a 5,500 lb car.

  17. Love the power just having a low fuel pulse #6 cylinder replacing everything need fresh views on this

  18. I love my 8.1L! I have a 2002 Chevy Silverado 2500HD with the 8.1L and an Allison transmission. It is the most powerful and fastest truck I’ve ever driven (aside from those that were not stock). I am very interested in Raylar and what they can do for my beast. The only problem I have with it is that it was burning oil until I switched to a heavier weight. It recommends 5W-30 but I switched to a Dello 15W-40 and it’s sooo much better in that regard. The other issue I’ve had is breaking tires loose and loosing traction very easily. With that much power, it’s easy to understand. Pulling a trailer this truck runs and performs better as it’s too light in the rear for that much power. I bought it as a farm truck and back up but now it’s my every day driver just because I enjoy driving it so much!

  19. hay guys, i save gas with my 2003 gmc 2500hd 8.1L and drive about 87 miles to a lake pickup my rv trailer set it at the lake enjoy come home and drive my 2003 dodge 4.7l thanks

  20. I forgot to get back to the site and this is a great site. Thanks for your suggestions on the tuner it sounds excellent. My 8.1 is a 2003 GMC 2500 HD with the 5 speed allison that I bought new. I feel the allison trans is perfect due to its gear spacing for the 8.1 Other trucks I have had get caught between gears (spacing) as the drop in RPM causes the engine to slow to much etc. Two things I didn’t like with my diesel trucks were the oil gets real nasty and if it leaks on your driveway if is not coming of for awhile and black stuff (like particulates) gets all the engine compartment. If you work on the engine you come out covered with black stuff. With the electronics washing the engine off was a bad idea for me. I pull horse trailers and somehow they have extra drag to them. I cannot explain why they put more drag on the trucks. Maybe they are built extra strong/heavy to protect the horses but even small empty ones have a lot of drag. I pull race car trailers and never a problem. My trans will throw a code now and they when I take off fast trying to merge into traffic with a heavy trailer. A transmission shop that does a lot work on modified diesel truck said they could improve the fluid pressure which would fix the problem (for 2,000$). Some the the tuner kits talk about transmission pressure?

  21. Came across a 8.1 and plan to swap into my 66 Impala. Having trouble trying to find a kit that will bolt up the engine to the stock mounts. Anyone have any idea where such kit exists? I’ve called Raylar and they flat out said, “nope, no kit that we know of”. Also picked up a 4L80 trans to match. Any help is appreciated.

  22. Very interesting article. I have found an engine in the crate with the following numbers: 122556105; 10XJB; W982435453.
    Would this engine be the Vortec 8100? I’m trying to figure out what to do with this baby. It’s strange looking to me.

  23. I have a 2007 GMC c5500 with a 8.1 with a big hole in the block. I have been trying to find a replacement in central Maine with not much luck.

  24. I have a 2004 Chevy 2500 with a 8.1, it has a bad knock and mechanic said over $3000 to fix it, my son found a 2001 8.1 our of a Chevy truck are they interchangeable, he thinks the electronics are totally different

  25. Ordered my 2500HD Crew Cab 4×4 with 8.1/Allison in 2004. This truck was my daily driver until 2010. It is now used to tow, hunting/fishing trips, & hauling things. Mine has cold start knock, but quiets down after about 30 seconds. Doesn’t burn any oil and gets consistent 10-12.5 MPG.

    Read an article about the 8.1’s development by a GM engineer. He said this engine was designed for extreme-duty use — medium duty trucks, generators, etc. They even use the 8.1 as a pony-motor to start huge diesel marine motors used in ships. He felt the 8.1 in a light-duty truck was overkill.

    I repaired rusty rockers, cab corners, and rear wheel wells (come on GM, fix the rust problems!!). Mine has only 134k miles…I plan on keeping it for a very, very long time.

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