I am building an engine that i hope to make around the 500whp mark with. I have built the black and am now moving on the head. At the moment i am going through the process of deciding what im going to do and pricing it up. I will do a set of 272 cams, upgraded supertech valve springs and retainers but what im stuck on is the valves. I want to know if the standard valves are ok in terms of strength/performance ect. I will have the engine shop check them and the guides and replace if needed but if that all checks out fine i would like to get the carbon cleaned off and maybe a light lapping into the seats. Also i am not really interested in going oversize or getting the head ported. Thanks in advance for any responses.