i'm lookin to put a air intake,exhaust,and programmer in my 03 cummins diesel what size should i buy?

 

First; is your truck common rail injection, or does it have a VP44 injection pump? If it has the vp44, get a fuel pressure gauge ASAP!! I think the switch was in the mid year change in '03.
4" turbo back exhaust is usually the best, unless you're going mega hp.

 

how do i find out what one i have i know there is no cat on it if that helps they didn't start them till mid 04s thanks for your help too

 

how do i find out if i have a common rail or a vp44 injection system

 

Heres some VP44 info for you. http://www.mwfi.com/vp44_Installation_info.htm Look under the hood and see if you have it.

 

you should have a common rail on the drivers side there is a fuel rail sitting on the side of the valve cover that's a common rail and a VP 44 pump has single lines running from the injection pump to each injector
If you have common rail I have a 04 CTD 3500 that's got auto trans, shiftkit, stall torque converter, intake, exhaust turbo back, bully dog power pup

stock injectors, stock pump and its my daily driver with a 19-20 mpg city
you could get all that and more if you wanted the only thing i wouldn't get is the power pup It don't monitor anything of course its cheaper then the one that does but i would rather have the bully dog GT. It does monitor the engine and boost.
where I bought everything at EBAY and installed myself.