valve clatter

[USMC302]

Awesome, ok, the air/fuel ratio is at exactly what? It's normal to jump around at idle, the computer tries to achieve a 14.7 mix, you need a real air/fuel meter to really tell how lean or rich it's running. The sheetmetal valve covers will def let tons of valve chatter out, but it's still safe to go ahead and be sure the valve lash is set, if you take the valve covers off, make sure none of the roller rockers are loose enough that you can lift one off the valve, side to side movement is ok, just not up and down. Most of the time they will need to be re adjusted after the first few hundred miles or so anyway. The oil pressure will generally be lower at idle and higher though the rpm range, nothing out of the ordinary there. Your fuel pressure sounds extremely high for 30lb injectors N/A. You should try bringing it down to around 35-38 for a test run at the track, don't pay attention to ET, look at MPH, take away fuel until you slow down.