256 is not the standard duration at all,
Cam Timings -
Inlet Cam - Duration - Lift
'Big port' 240° 7.56mm
'Small port' 232° 7.1mm
4AGZE 232° 7.1mm
Exhaust Cam - duration - Lift
'Big port' 240° 7.56mm
'Small port' 232° 7.1mm
4AGZE 232° 7.1mm
256' is the most lift u can run on a stock ECU