Edelbrock 60555 Performer Series RPM Cylinder Head Complete 525-650hp Rect. Intake Port Std. Exh. Port 118cc Chamber Vol. 2.19 Intake/1.88 in. Exh. Valves Single Performer Series RPM Cylinder Head Edelbrock 60555 BBC Performer RPM 454-R Cylinder Head - Assm. Product Dimension (LxWxH): 25.7x11.1x8.7