I will not do base gaskets on an EVO if the customer will not let me put on Hannas' base gaskets. About 8 dollars a piece. Make sure your cylinder studs are tight, it is very common for cylinder studs to work loose causing the leaks, on EVO's and TC's. Any time I pull off a set of heads and cylinders I alsways double check cylinder studs for loosening. There is always "always" at least one loose. Get yourself a ball bearing ( so the head bolt dont stick ) and put it in the short head bolt, then screw it down on the stud, then tighten it up. With the ball bearing in the head bolt, it will break loose and not undue the stud you just tightened. That and the base gaskets ( hannas' ) and you will be fine.