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Cummins B-Series Parts — ISB, 6BT, 4BT & QSB

Heavy-duty and mid-range Cummins B-Series parts for the ISB, 6BT, 4BT, and QSB platforms — injectors, cylinder heads, gaskets, turbos, and full rebuild kits in one place. Whether you're working a mechanical 6BT, a common-rail ISB, or an industrial QSB, we stock the wear items and overhaul components pros reach for.

Not sure a part fits your build? That's our edge. Send us an OEM, competitor, or superseded number and we'll cross-reference it to the right B-Series part — then quote it fast. Cross-reference a part number or request a quote. Most orders ship same-day from Colorado, with free freight over $1,000.

Showing 24 of 297 Cummins B-Series Parts — ISB, 6BT, 4BT & QSB

Choosing the Right Cummins B-Series Parts — ISB, 6BT, 4BT & QSB

Heavy-duty diesel components must be matched to the exact engine and application. Before ordering from this collection, verify the part number, engine model, engine serial number, and any casting or calibration number shown on the original component.

Fitment information to have ready

  • OEM, dealer, casting, or interchange part number
  • Engine manufacturer, model, and engine serial number (ESN)
  • Truck year and model when the component is chassis-specific
  • Core details for remanufactured or exchange components

Need a fitment check?

Use the OEM cross-reference tool or text a clear photo of the part tag to (720) 445-6249. A JAK'S Diesel specialist can confirm the match before the part ships.

Got a Number We Don't List?

Text a photo of the part tag — a specialist crosses it and quotes you fast.

Text a Part-Tag Photo(720) 445-6249