Intake Valve Seat. Fits Big Twin 1966-1984.

* Easy oversize identification by the part number

* Easy to machine with cutter and stone

* Resists severe pounding and dissipates heat better

* Work-hardens during running-in

* Radiused for easier installation

* Replaces OEM # 18018-66

* Replaces OEM # 18056-66B

OD = 2.135"

ID = 1.750"

Thickness = .400"