Do you have a LB7 or a LLY engine-? An 04 can have either.
Check the 8th number in the VIN-- a LB7- "1" a LLY will have a "2"
The filter heads are the same, but there are other differences which may cause problems.
Chevy 04.5 LLY, 2X, shell, XDR, MikeL Heavy duty up-grade, 6spd, TransGo, deep pan, de-badged, 65 Gallon replacement Aero tank, LBZ-mp, Kennedy pump, shimmed, Pre-fuel filter, tow mirrors, BU cam, gauges, GPS, Sirius, bags, custom grille, fender vents, HD trans cooler- Curt front hitch, footwell lights, load lights, Studs, head gaskets.--- Jerry