I didnt think you had to torque the orings head AS  tight.You might have pinch your orings.I thought you just got them tight and use some silicone on them. That might be your problems their

Do not use any type of sealer on the o-rings. 

Any and every head should be torqued to keep the bore round and minimize distortion.  The head bolts do not have to be tight to make the o-rings seal but they have to be tight enough not to vibrate loose.  18 to 20 ft-lbs should be the proper torque spec.