Can anyone tell me what the big differances are between the 03 and 05 engine are? I already know about the Turbo, 03 HE341 vs HE351 on the 05.
My nephew got an 05 this summer and I have an 03. I loaded my smarty jr on his 05 and it really seemed to make a bigger differance on his 05 than it does on my 03, same settings. I have done the HE351 upgrade on my 03 even before i loaded the smarty on his 05. Just wondering what else they did different on them. Thanks in advance.

 

Pistons, injectors, programming. The 04.5 have a cat.

Not sure if you're supposed to load S03 software on an 05...

 

Thanks Madhat but now you got me confused, which doesn't surprise me. The smarty I have is a J06 which is to be for the 03 to 06 5.9 which I got off of Mr. Ellis on here. So I guess what I was looking for was things like injectors, pistons, cam, etc. Your right the 4.5 and up had cats but that is long gone on his truck. And looking at injectors my local dealer claims the injectors are superseding part numbers so I would assume they are the same. The injectors being different or maybe slightly higher rail pressure is what I was thinking it might have been but I guess well never know for sure will we.