A friend bought some used and they were ported wrong. They made both sides of ports maxed out. It looks like the inside ports are the bad ports because the inside head bolt causes a bump right before the valve throat making flow have to s around that wall. Now intake port wall is laid back right to it and has made the s worse. I told him i would epoxy it back flat some and try to sandroll some of the bolt hole back some if it was me. I would think widening ports roof some to help flow turn and the regular trenching and triangling of guide with some slight short turn would help. One big question is this head has alot better short turn and this make the floor go up hill and the also makes the port longer, good for torque, but on a race 455 i would think it could be flattened about .050 to .075 and make it flow more at high lifts?? 660 lift cam with like 310 dur. advertised too big in my oppinion. It really pinches the port down alot at the crest and at roof in front of guide, Best would be to fill floor flat with epoxy and raise port accordingly if there enough meat i would think. I know we need to backcut the valves and do some chamber work. He is kinda on his own here with BBC thinking they are king and would like to see him get close to 600HP. He has milled them .040 and have read you can go 80-100 thousands , is this true? He is only around 12 to 0ne with the flattops, ported torker. Randy or anyone else have any sudggestions about build we would appeciate it.