whats better to build 03 or 05

[scarecrow734]

what would be the better , more reliable , better mpg , long term daily driver , tow rig to build up to the 600 - 700 horsepower range. a 2003 cummins , auto trans or a 2005 cummins - auto trans? I know the 05 has the higher stock hp , tq numbers.

 

[Kill]

2006

 

[wildman6bt]

The transmission is 48re and is the same in all except a few early 03's that got 47re's.
03-04 is said to get better fuel mileage but if your modding it that's out the window.
06-07 you can tune with EFI Live, 03-05 smarty is the best tuning.

 

[silver2004]

It's almost the same truck. I think either one will be fine. The 03 Cummins does have a less prone to melting piston design but I've also heard of the 03-04 being more prone to dropping valve seats when egts are real hot. Just don't get either one hot and you'll be fine. The differences in hp and mpg basically go out the window once you start adding air, fuel, and tune. 06 you can get EFI Live software tunes!