I am a powerstroke guy, but I know that it would take a lot of money to even get close to the hp that cummins and the d max can produce.  I absolutly hate duramax so I decided I need to invest in a Cummins. I dont really know that much about dodges, so what year of truck would you guys recommend that I could beef up to make LOTS of HORSEPOWER? Also what modifications would you recommend doing to it to get atleast 5-600 hp?  

I like the Commonrail, so I would recommend a 04.5 and up.  I truely believe that Commonrail injection will be king in time.  

This is the first step.  More air, more fuel

First is first, more air.  I would recommend getting an exhuast, preferrably 5 inch just because they make your truck sound like a beast and it lowers EGT's straight pipe mandrel bent.  After that get a CFM intake and Air Intake. These two will significantly increase spool up time, lower EGT's and give you better MPG as well.

Once you get the simple ones out of the way, chip it out bro.  I would recommend a smarty simply because they're the best for the Dodge and they're specifically designed for dodge and dodge only.

Also when you get the chip, make sure you get a torque converter and valve body as well as guages, boost, pyro, and tranny temp.  These two upgrades (converter and valve body) alone will dramatically increase the durability of the crappy tranny dodge has, you can handle around 500-550hp.  Torque converter prevents slippage and cools tranny as well as improves MPG, and Valve body increases line pressure and gives firmer shifts, dont forget the DOUBLE DEEP tranny pan to keep it cooler.  With ALL your transmission upgrades I would recommend Goerend Transmission, they're the best on the market, and their pricing CANNOT be beat.  Don't do the ATS 5 star converter the 5 disk clutch is only for selling purposes.  You'll never make that much power and torque with what you're saying you're wanting to make in order to utilize it.  Also I would get a boost fooler which will give you around 10psi and lower egt's as well.  Also gives some power too, and it's cheap.  You will need it anyways once you stack chips.  Another thing you will need is a lift pump.  This is critical, simply because if your liftpump struggles so is your whole fuel system going to struggle, it's gonna tear up your fuel system in time if you don't.

Right now once you get those upgrades.  Youre truck will be around (if using last setting of the smarty) 450-490hp and 800-890ft lbs at the crank.  You will be getting substantial airflow, lower egt's, and have some decent power.  Now we go a step further.

Here is the second step. fuel, air, cooling, and keeping your motor together

For the next step.  I would recommend stacking those chips.  You can do either of the three for your application.  MP-8, Edge, TST.  I know TST is a CRAZY CRAZY stack withe the smarty.  And if you go edge, either do a juiced with attitude, or if you get the TNT-R tune (which I don't recommend for your application) then go with the Edge EZ.  The MP-8 I don't really know to much about.  I apologize.

When you stack chips, this is when you have to start safeguarding some things.  For one, you will more than likely be over 40lbs of boost, in cummins engines you will need headstuds at least, and for what you're wanting you will be fine with just headstuds.  I would go with ARP, but there might have to be some clearancing in the back right of the spacer plate.  An aftermarket turbo now will be the next think you will need. I would recommend either an Industrial Injection (because they're kits are unbeatable as far as being complete) or ATS (the wastegate their turbos now, though the kit isn't as complete yet).  Once the turbo is on, I would recommend something else.  Water Methanol injection.  It's gonna lower EGT's VERY NICE and give you around 70hp or so.  Also creates a scrubbing effect in engine and cleans it from harmful agents.

Now that you have those nice little upgrades.  You're engine will be running extremely healthy and you're boost will be somewhere around 40-48psi.  Also you're hp will be around 550-590hp and roughly over 1000ftlbs at the fly wheel.  You'll be delivering good amouts of fuel and you will be utilizing the fuel with your new turbo thus bringing your fuel to air ratio back to a balance.  Now here comes the major upgrades, kind of expensive but will definitely put you where you want to be.

Step three  keeping fuel pressure at a constant and dumping more fuel.  TRANNY WORK!!!!

You run stacked chips, this will ruin your CP3 very fast.  I would recommend a stage II or III CP3, personally by Floor it Diesel (the father of them) or Industrial Injection (who Floor it made them for only to have them stolen from Floor it).  This will restore you rail pressure at a constant level through out RPM and speeds.  Once you get that taken care of, the next thing is injectors. But don't go REAL big.  I would recommend Flux injectors by F1 Diesel.  They're very cheap and they give the best hp with best EGT's.  I would recommend flux 2's for you.  They add 100hp and will open up your truck like you wouldn't believe.

Once thats done, you need to do more tranny work, this will take some time however because it's your shafts, those will be the weakpoint and if you do boost launches, you will turn the internals of your tranny into chocolate pudding.  Do a input, output and intermediate.  Once you get those taken care off.  Your tranny will withstand ALOT of power around 900 to the ground or so.

Ok so all in all, once you get those parts.  You should be anywhere between 650-700hp and 1100-1200ftlbs at the crank which would put you where you wanna be at the wheel.  500-600at the wheels.  It's gonna cost you though, but trust me.  The next time you race a mustang gt that thinks he has got something but then you smoke screen him, it's TOTALLY worth it my friend.

However, before you buy these things.  PM ME and I will give you a number to a guy in California, he has THE BEST pricing I could find for any product I have bought.  Hopefully this helps my fellow cummins owner.

Good luck bro

John  

Also with ATS and there turbos, they are made a CNC aluminum which really helps in spool up.  No other turbo has that.  

It wont be for a while yet til I do this, as I just started looking for a truck. I will probably get one with transmission problems and bad injectors, turbo, etc., so it will be a lot cheaper, and I'd be replacing them any way. What is the oldest cummins I could go down to? 2nd generation or what?  

You could do a late 90's 12v if you wanted.  Or the 24v, before the Commonrail.  I am sure those will be pretty cheap as far as parts.  I know the 12v's are.  They're ridiculously cheap  

Everything on the 12valve is virtually mechanical too.  Which is good.  

jms has a GREAT point. the 12ver is awesome when it comes to fuel delivery and mostly every delivery. it is all mechanical while all 2nd and 3rd gen is all electronic. i got a 24 myself 02' auto, STAY AWAY from the 02' auto. the turbo sucks unless you plan on replacing it anyway. im not a big fan of the common rail. stick to 99 to 02 cummins. per. hd 6speed.  

My signature will give you a clue on what to do for right around 600HP and run mid 12's in the quarter.

Make sure you do the Tranny First!!!!  For that HP level, you better get FULL BILLET!!  All 3 shafts!!

I twisted my stock intermediate shaft in half with my Lock Up Switch!!!  

Hamilton Valve Springs , an O-ringed head and a set of Twins are next....Sometime next month I hope..  

See, thats the thing.  If you do stuff like that, and I am not trying to be cocky or a smarty guy.  You have to do it the right way.  Safeguarding is a most definite upgrade.  You can only go so far as the fuel you dump in, then only so far as the air you dump in, then only so far as you cool everything, then only so far as your tranny will allow.   Safeguarding is everything, performance is nothing unless it's not safeguarded.