Ford SB (289-351W), Straight PlugIntake Port: 185ccChamber: 64ccStage 1 Assembly: 1.265" Spring (Hyd. Flat Tappet)
Ford SB (289-351W), Straight PlugIntake Port: 185ccChamber: 64ccStage 3 Assembly: 1.550" Spring (Mech. Roller)