2001-2004 GM 6.6L DURAMAX LB7 MBRP GMCA425 3" TURBO DOWNPIPE (50-STATE LEGAL) 2001-2004 GM 6.6L DURAMAX LB7 The MBRP GMCA425 3" Turbo Downpipe eliminates the restrictive factory downpipe in your 2001-2004 GM 6.6L Duramax LB7. Featuring a mandrel bent aluminized steel construction, the MBRP 3" Turbo Downpipe provides... MSRP: Was: Now: $449.99 Add to Cart The item has been added