This Small Block Chevrolet Aluminum Eldebrock Perfprmer RPM 4BBL Manifold is a Dual Plane design and was only on our motor for a very short time. This Manifold has not been modified in any way and is ready to mount on your Hot Rod now.It is in very excellent condition and was designed for Low and mid range performance. If you need it installed I am your performance Hook-up with over 45 years of experience. My rates are right around 20.00 per hr. Give me a call with Mopar being my speciality. Thanks, Vic