1965 Chevy Rectangle Port Head Square 396 427 Big Block Cylinder J 1 5 Chevrolet. This product data sheet is originally written in English. 1965 Chevy Rectangle Port Heads Square 396 427 GM Big Block Cylinder J 1. HARD TO FIND ORIGINAL CLASSIC CAR & TRUCK PARTS. Thank you for allowing me to share my passion with you. I have thousands of original car and truck parts available in my store. All of our packages are professionally packed with a custom made box from recycled cardboard. This will take a little longer but you’ll be pleased with the care that was taken with your part. See our other items. Hard to find early square port head removed years ago and stored away in the back of a machine shop ever since. Nice original GM head for rebuilding that is showing some polishing. See pictures for condition and wear as we rely heavily on photos. Applications are based upon various sources, although I try to make sure research is correct it can be flawed so please verify your applications. Please use a PC to take advantage of the zoom feature as it will provide much greater detail than a portable device. 1965 Chevy Rectangle Port Heads Square 396 427 GM. Big Block Cylinder High Performance J 1.