I think this is basically a trial and error thing. You can't predict what's going to happen when your changing the timing of your valve's opening. Your going to be creating more overlap which may turn out to really benifiet you all though you may want to reasearch how much overlap your engine has already, because it you go to much you might actually start pulling some exhaust gas back in, or losing some of your air fuel mixture. I'm also an idiot i'm just trying to give some insight I may be a little off.