Heads, Serdi competition valve job, 2.02" intake, 1.60" exhaust valves. Bronze valve guides installed and honed, intake and exhaust ports gasket matched, Chambers radiused, Cat aluminum extrusion rockers. 1.6 ratio heat treated roller tips, extra large fulcrum needle bearings.. These are cast iron heads not aluminum heads. I personally do not yet understand what all this information means. I am just in the learning stages of this hobby. I am simply forwarding to you what the previous owner has typed out for me in the album that came with the car detailing the restoration process that was done.