MCS-503608 - Replaces OEM 8990/A style ball bearing. This bearing will fit will fit all models as front & rear outer cam bearings. The MoCo redesigned the Twin Cam rear outer cam bearing from ball (OEM 8990/A) to a roller bearing style (OEM 8983/MCS 921138) in 2001.

Fitment:
99-06 Twin Cam (excl. 2006 Dyna) (NU)