keep the boost around 18# and keep the timing lower than 19deg and youll be fine on a cobra mod motor. and im pretty sure it will put down some impressive pump #s for a 281ci motor! then the power level comes into question…but anyways, alot of guys on CF seem to think that this zr1 was the red one that popped its motor for some reason, but the guy denies it. (guy also doesnt drive the car, his 340lb driver does LOL)