I'm pretty sure it's not a direct bolt in because of the exhaust outlet and air outlet connections. It will bolt up to the manifold though, search for HE341 info. I think HE351CW's started in 04, 341's in 03.
I'd say if you can get them for free, it's definetly worth it, and a step up from the HY35 you have now. An 03 down pipe and some sort of adapter for the air outlet would get you going. Good luck.
98 12V QC 2500 Flat Bed 4x4
Curtis 8ft plow
07 5.9 Mega 3500 SRW 4x4