Talking to my engine builder/machinist about which head he prefers for my build (512 on a 400 block, hyd roller, emphasis on torque) and he told me to get the bare castings. He said that he has been seeing not quality springs and valves on the assembled heads. He said he has seen this on the Ford heads as well as the Mopar. Seeing how an assembled head is only a $100 more than a bare head this may be true. My question is assembled or bare? The head I would get assembled is the 17802 head. Thanks