This Offenhauser carb adapter will work on their flathead 4 brl intake manifold (also Y-block Ford and other apps) to put on either a Carter AFB, Edelbrock Performer or Holley std bore 4 brl. (AFB or Edelbrock won’t work on 48 and earlier engines because of the water outlets). The manifold base measurement is 3 & 7/8″ X 3 & 3/4″. It is prox 1/2″ thick.

Quad Adapter C Carb. On either Quad Adaptation A or B Base