Cummins Cast Aluminum Flywheel Housing for B-Series / QSB Diesel - Used

**Cast Aluminum Diesel Flywheel Housing (SAE Bell Housing) — Used Take-Off** **Application:** Cast aluminum rear flywheel housing with integral starter bore and full SAE transmission/gear flange. Casting characteristics are consistent with the Cummins B-family (4BT/6BT/ISB/QSB 4.5–6.7) used in marine, industrial, and truck applications — application is not verified, so this housing is sold by photographs, identifiers, and dimensions. Cast number read on the rim: 3967336 (casting number, not an orderable OEM service number). Additional cast foundry marks: X1U7 TD, FM1, MADE IN USA. **Condition:** Used, untested take-off. Complete casting with no cracks visible in photos; surface dirt, light rust staining on hardware, paint scuffs, an old wire lead at one boss, and some broken/retained hardware in lower flange holes that will require removal. Mating surfaces, threads, and pilot bore have not been measured or crack-tested. **Approx. 20 in x 19 in x 9 in, est. 40 lb shipping weight.** Buyer must confirm fitment by part number, photos, dimensions, engine model, serial number, and application before purchase. Used marine part sold as-is unless otherwise stated. No returns on electrical, used, special-order, or installed parts.