If i go with a .041 head gasket how much lower will that make my compression.I had .039 gaskets on the motor.And if i go with the .041 head gasket how much can i shave off the heads to up the compession. I had some fel pro 1003 gasket that i bought and didnt use thats why im asking.The motor is a sbc 406 with flats tops,64 cc heads