Edelbrock Cylinder Head BBC BV3 Pro Port Hipd 11 Deg Intake Valve Extended Exhaust FlangeEdelbrock Part #613669 is a Pro Port head that requires professional porting prior to use since the ports and chambers are deliberately undersize to permit a wide variety of end applications. The head has an 11" intake valve angle and is intended for high output, large cubic inch, 4. 84" bore spacing (stock) big block Chevrolet racing engines. The 613669 employs a symmetrical port head architecture similar to the Pro Stock DRCE3. The head is treated