Ok, let's have an actual serious discussion about Dmaxes and Cummins.  The Duramaxes have waaay better flowing heads than the early 12 valve Cummins, although it questionable whether they are quite as strong.  I know of a few over 1000rwhp, and with a good set of rods and a stud girdle it doesn't seem like any have scattered yet.  There are quite a few 12 valves over 1000hp, and they seem to rely on massive amounts of boost (100+psi) to do it.  My take is that the Duramax is a more efficient engine that is probably not as strong as the Cummins, but the Cummins needs help in the airflow department to make power.  Common-Rail Dodges seem to be holding their own pretty well, although I don't think they have caught up with the older engines yet.  As for what kind of engine I would build if I had the money?  A stroker 6.7 with a p-pump    

Well i dont think this is entirely true. The Duramax may have a better flowing head but with a little machine work you can make a Cummins better that easily. When you do machine work to a Duramax you cant get much out of them because they are already to the max from the factory and you cant get much better than whats already been done. The 12vs, yes they need quite a bit of boost to make serious hp but you forgot something. They have to run a ton of fuel and that would be the reason to run big turbos. If they didnt run big turbos they would simply over fuel and burn down. There is a Duramax in Ft. Collins that went on the dyno after me a few weeks ago and we put down the exact same hp number, of coarse i out torqued him by alot. If the Duramax was as fast as everyone claims i wouldnt have kicked his ass on the drag strip. It wasnt even a race i pwned him so bad. I could have beat him in reverse! And then he claims he gets better mileage, ha! After all that i still got 18mpg to his 14. Yea the D-Max being more effiecient, yea right. The inlines are always going to be on top. Less moving parts = more power, better mileage.  

i know if i had 2 choices on which one id pick to make a hot rod out of i wouldnt be in the thinkin process to long...definitly the cummins if nothing else its cheaper to build and you can actually work on one without removing half the engine first...and its hilarious E2 that after yuo spanked a guy in a drag race he would bring up some meaningless claim about mileage. thats good stuff  

We had a 04 5500 chevy with the 6.6lly in it and wih out a edeg tuner it would not pull it self and a 30 ft gooseneck trailer with a sod installer and bobcat down the highway and went into the shop a couple times for the turbo and a few times for the allison auto. Our last dodge a 3500 4x4 6sp we traded off at 140,000 and it was wore out neede new brakes, shocks, clutch was goin out. but the cummins was still goin strong.  I would rather have a cummins the a duramax from personal experiece.  

I have absolutely nothing against a duramax, but i have personal experience with both (powerstrokes too, but thats a whole diff. topic, lol), and i really dont feel like ther's much strength to the duramax. Most of the time ive spent driving a duramax i was towing, but i cant think of a better way to test a diesel. I have to give it to the duramax, in stock trim, they are pretty quick, as far as automatics go (stock ones anyway), the allison definitely feels stout, but back the cummins with a 6 speed and when it comes to towing, you cant beat it. I know, i know, comparing autos to manuals it like apples to oranges, but thats just the way it is. Ive never hooked a duramax up to a load that it wouldnt pull, but if it was real heavy it felt like it was used up already, like it didnt have much left. Now i have to admit, with the stock trans and 237,000 miles on my 99 dodge auto, it didnt pull for *** it always felt like it struggled. I dont have any eperience with the high flow this and that, ar much else past the basic intake, tuner, exhaust combo, but stock or close to it, i definitely think the cummins has it beat, maybe its not too much faster, probably about the same, but the cummins parts are (usually) cheaper and the motors are way stronger. But its all really opinion, or budget, or maybe brand loyalty, whichever one it is, everyone sees it different.  

I have nothing against the Duramax at all either its just that i have had way better expirences with a Cummins. Out at the ranch in the winter the snow will drift up on the roads and we dont always have time to clear it because we are taking care of livestock and equipment and w/e else and this past winter we got a real test on the pulling power of the Cummins and the Duramax. After i got my Cummins in feb i had just put the leveling kit and 35s on and it snowed over night and in the morning the wind picked up and blew the snow in 4ft drifts across the road in someplaces and 12ft in others. This doesnt sound bad but when you are pulling a 18,000 pound trailer it can get pretty interesting. The Cummins struggled a little in the deep stuff but seemed to have the raw low end STOCK pulling power that the Duramax didnt. The Duramax was modified and it struggled everywhere. It was ridiculous. Cummins all the way.  

My chief has a pretty nice Duramax that runs like 12's I think. It's a decent truck, with a lot of horse, but not as much low end torque as I would like to see with the amount of money put into a truck like that. Perhaps he just built it for more speed than anything. Anyhow, I dont have a Duramax, and I've only driven one once hooked to a load. With that aside, I'm MUCH more inclined to drive a Cummins. I have put that truck through pure HELL and it still drives for me just fine. Gotta love the Cummins!!  

A couple of my friends have Duramaxes and one of them has an 04 lly that is pretty quick, will give my 06 Cummins a run for its money until i catch fourth gear then i pull him till i either back out of top out. Duramax is a good truck dont get me wrong but his truck hooked to a trailer just seems like it has no power compared to the Cummins. Just my opinion.  

I just traded my 05 cummins in for a 06 duramax.  My dodge had the six speed manual and 67,000 miles on it.  15,000 on a new engine because the injector stuck open and burned a exhaust valve and melted the piston.  66,000 miles on the truck and 14,000 on the new engine and it blew the frost plug out and lost all my antifreeze.  New frost plug in and 6 new injectors for the third time and I unloaded it to a dealership for some poor guy to have.  

^^^ that sucks man  

I have an 03 cummins and my buddy has an 05 duramax. He put some different rims and tires on that were true 33s. he said that he could feel the power loss. I put a set of 35 on my dodge and i have less work done than he does and it didn't effect my performance at all. I love my cummins and will never get rid of it even if diesel prices r ungodly. I have put it through hell and back and it has never left me stranded out on the side of the road or in a muddy field.  

I think the great dividing factor is what you need out of an engine and intern the truck it’s installed in. My preferences won’t help some but if you’re like me, and I will try to elaborate then perhaps this will help. I need a truck that can be a workhorse once every two weeks and a daily driver the rest of the days. Basically I want a fast diesel primarily that can function as a workhorse in a pinch. It has to be in a truck that looks slick and is draped in buttons and options I’ll never figure out how to work a.k.a my Texas Cadillac. Cummins is a workhorse born and bred from its straight six designs to the stock Jake brake they now come with. From my experience this means low end grunt with lots of noise and drama. If I had to tow everyday I would invest in a straight six diesel so I understand the appeal it has to that section of the market. The beauty is I don’t have to work that hard anymore I get to enjoy some of my hard earned cash and the last thing I want is a loud workhorse. I want a fast truck that’s quiet and feels good inside and looks great on the outside. Somethin I can go roppin with or pull a boat to the lake with on the weekends. Basically I want the Cadillac of work trucks. Duramax is a v8 so I got my high end speed king performance when It’s just me and the family goin 150 miles  to see grandpa its perfect quieter than any truck I’ve owned and fast as all get out. Along with that I’ve had some fun and raced a few Cummins when loaded and haven’t been passed once in fact I’m usually the one tipping of the hill first. Granted the loads we were carrying that day were 10000 pounds or there about so it doesn’t really push these trucks to their breaking point. So for me it all makes since for my situation Duramax has my vote this time and Chevy always will. Aside from Engines I found my dodges to be very cheap inside as opposed to the escalade fixtures I get in my Silverado. Granted this does help the price go down as far as the sticker goes. I don’t expect my Duramax to outlast or out pull a Cummins I do expect it to give me trouble free performance for 100,000 miles be good lookin inside and out and be full of leather and LCD screens and buttons I can’t understand. So in short if you need a workhorse everyday get the Cummins if you need one once in awhile and something to show off in town get the Duramax. But to tell you which is better that’s hard like askin which color is best to paint my house without telling you about the neighborhood or region or what my house is made of. Just depends on your needs. However The two Cummins I’ve owned have been junk my 01 was slow lacked power and was always in the shop and to no surprise my 08 blew its turbo with 1700 miles so even if I did have to go back to work lol I’d still choose a Duramax I know everyone swares by Cummins reliability but I must of gotten two sour apples and its spoiled me permentally. 1st time burned your fault 2ndtime my fault there isn’t gona be a 3rd time. They say you get what you pay for don’t let that higher price Chevy dissuade you your getting that much more of a better truck. I traded my 08 Dodge for my 07 Chevy and well ill keep you posted so far not one problem.  

The Duramax is just the greatest plain and simple if it wasnt for the Duramax, Cummins would have always stuck to the crappy inline six but now they are switching to V8s because everyone knows that v blocks are more efficient and more powerful. There hasnt been a trailer that this truck couldnt tow. I have hooked to loads as heavy as 12,500 pounds!!!! And no problems what so ever. I even race this truck and tow my moto trailers to races and it never lets me down. Gets 16mpg to boot.  

"everyone knows that v blocks are more efficient and more powerful."

Everyone? I guess you forgot to tell Cummins,Cat,Mack...ect...haven't seen to many transport trucks running V blocks and last time I checked they always seem to pulling something...Do you really think they all got it wrong? Wow! you could really be on to something here. I think you should go to these world leading, technologically advanced diesel manufacturers and tell them your theory. maybe they will name an engine after you...Come on what are you waiting for...the world awaits your brilliance!  

Is he trying to dumb us down?