First of all you need new headgaskets...you can't reuse them. Either get stock or spend the $500 or so for some Greddy metal head gaskets. Then make sure you torque the heads down to spec like the service manual says.... tighten, loosen, and then retighten...and the first torquing of the heads is not as tight as the final torque figures... I think it's first like 30 lbs. then loosen then tighten to 90 lbs... I can't remember, check the service manual.