I hate to be simple. ur doing port ? udoing polish? you ask tell all of us. work on any head is not as by hand simple by hand. a good way is to have valve job done. company a good one. take heads any and u get some measuring stuf as in cooking. take this for chamber head.. valves closed heads level take and put or inject fluid into open chamber on head block side turned up and level measure. that's ccd.. do the same 4 intake port and exhaust port keep turning with valves in head. port and redo same to ck ur self.. . as good as any volume is what works. now smooth and flow cones second.